I think as Sonar users we are a little spoiled by not really having to contemplate latency calculations to keep everything in sync because Sonar just does it automagically in the background. I had never even considered such things until about a year and a half ago when I was plowing through the free month of Groove3 the bakers gave us (man I wish they'd do that again... lol). A lot of the more general mixing vids I watched were Pro Tools based and a couple of them detailed the process of engaging that tool or whatever to gauge how much latency is being produced by a particular effect and then how to compensate for it so everything was playing back at the same time. Seemed complicated at the time and I'm sure there are ways to avoid having to go through that process everytime you insert a plug in PT but it was very eye opening in regards to how much of a PITA things can be when you don't have idiot proof features doing the grunt work for you.

sock monkey
Cakealex - one thing- 
 
"and you can a VST compressor into the chain (no need to fork out for a real compressor)." 
 
This is not true, You cannot compress before you hit the A/D with a VST compressor which is the why some of us work this way in the first place.

That is true my bad - I was typing when fast asleep.~ The rest of the post was accurate though.
This reminds me I need to get a cloudlifter for my SM7B to increase it's gain. Works well with the focusrite but I definitely would like more gain ideally.

A compressor doesn't really fix bad mic technique or bad vocal technique. Not saying the OP has that, but it's worth considering if there are massive differences in the dynamics of the recording.
I do use a preamp/compressor for tracking vocals but it's usually set to work very mildly. I tell them to sing it again if I really can't work with the recorded material.

Thanks for all the replies, guys. I did purchase the ART mymonitor, received it yesterday, and i'm really liking it so far with the minimal time I've been able to spend on it. Luckily I can easily return it if I'm able to find some way to finally get what I wanted within the Scarlett itself, so I'll be using some of these suggestions today and fooling with it one last time. 
 
As to some of the specifics asked, I'm using an AKG C214 mic, along with AKG headphones. Can't remember the model of those phones; they're not top of the line, not terrible either. Decent mid-range pair. 
 
I think my issues comes down to the gain I've been setting on my mic. When I set it initially, I would carefully watch the meters as I sang some test passages, and everything stayed in the green, no yellow/red. But when I would play back. louder passages would have a sort of clipped sound, almost as if someone had applied a way too-heavy brick wall compression on it. I had a pad that came with the mic switched on while singing. 
 
Anyway, I found I could remedy this by lowering the gain volume to the point where the green level indicator on the Scarlett barely comes on while singing these sections. The result is that the vocal doesn't have that "overly compressed" or distorted sound, but the result of THAT has been that the levels in the mix have been too low for me to really hear well, even with everything in Sonar's mix control cranked to full volume for the vocal and lowered as much as possible for the music mix. I tried to remedy that by applying input echo, getting the latency low and adding some compressor to the back end in Sonar while singing, and that's helped, but has also brought some other issues into the mix (pardon the pun), i.e., not totally comfortable now with the processed sound of the vocal coming through. I know, nitpickery. 
 
I think a lot of it comes from how I sing certain parts - very loud, very hard, and my songs tend to usually have some pretty big changes in dynamics. I've already done separate tracks for a "softer" verse and a "harder" chorus, so I'm not singing both of these parts on the same track during the same take. 
 
So yeah, maybe there's a technique thing involved that I need to work on, but I do know enough as far as when to back off the mic, get up on the mic, etc. In any case, thank you for all the great replies. I will have some time this afternoon to fool with this some more, but hopefully the above explains my situation a little more clearly. 

OK. A lot of that now makes a lot more sense. My wife is an extremely loud singer, and mic technique is everything for her, and she is the reason I initially went down the pre-amp/comp on the input stage. I only use it in moderation, but it helps to smooth out some of the peaks and keep the low volumes up there. But my biggest trick with her is mic placement, both in distance, and direction. I turn my mike, a Rode K2 valve job, just slightly to one side so that she sings across it, which allows me to keep her distance still close enough to get the 'close proximity' effect from my mic, which enhances the low mids a touch. So I think, by you knowing the probable cause, that you need to just keep working at it to find a happy solution. All the best..

That is definitely the type of thing that a) would require some kind of input limiting/compression (which is destructive and I personally think should be done AFTER tracking unless you've got some REALLY nice output gear and know how to use it), b) do multiple takes as you said, one with your input level set high enough to get a healthy signal for the quiet parts and a second one at a lower level so the loud parts don't clip your input channel (notice I said input channel... NOT the track in Sonar... I will explain further later) or c) go old school and have someone in the room riding the input fader (they would have to know the parts so they know when to do it and how far they have to go down in volume which is a simple calculation but who wants someone else in the room... I know I don't, especially when I'm signing... lol). Of course you could do that last one yourself but that might distract from your performance.
 
Now as far as overloading the channel input versus Sonar... the ONLY place you really need to worry about clipping is at the interface (if you aren't using any other outboard stuff like a preamp). Even if the clip lights in the track are going off it doesn't matter if the clip lights are staying out of the red on the interface.
 
The clip lights in Sonar aren't showing actual clipping that will be recorded (until when you mix down... then you may get digital distortion which is definitely unpleasant). What Sonar WILL show when you have recorded a clipped input is a white vertical line printed on the waveform. If you aren't getting any of those and you aren't HEARING any distortion/clipping then it does not matter what the track meters say.
 
From there you can simply automate if need be in the mix to even the levels out.
 
So do not look at the track faders in Sonar. Look at your interface LED's (which unfortunately can be a little inaccurate and they don't hold peaks) and right on the waveform for those thin vertical white lines. Most importantly LISTEN for clipping because that's all that really matters anyway.
 
I say this because you are saying you are getting yellow and red lights in Sonar. I get that quite often when tracking because I want a good strong signal and I know that as long as I'm good at the interface and I'm not seeing those white lines/hearing anything.
 
I used to be afraid of the track meter lights in Sonar and adjusted my input to avoid them. The result was really weak signals to work with which sucks. Things are much better now.
 
You may know all that but thought I would mention it.
 
Also I'm still learning so if I made any mistakes maybe some of the more experienced guys can correct me.
 
Cheers.

Oh yeah... mic dynamics is REALLY important too. Pros know when to back off the mic (loud parts/screams) and when to get right up close (quieter/more delicate work). I'm sure there are vids on youtube showing this.
 
Think of your microphone as an instrument that you need to "learn" to get the best out of. This type of mic control takes practice but makes a HUGE difference.
 

Kerch
Thanks for all the replies, guys. I did purchase the ART mymonitor, received it yesterday, and i'm really liking it so far with the minimal time I've been able to spend on it. Luckily I can easily return it if I'm able to find some way to finally get what I wanted within the Scarlett itself, so I'll be using some of these suggestions today and fooling with it one last time. 
 
As to some of the specifics asked, I'm using an AKG C214 mic, along with AKG headphones. Can't remember the model of those phones; they're not top of the line, not terrible either. Decent mid-range pair. 
 
I think my issues comes down to the gain I've been setting on my mic. When I set i hit initially, I would carefully watch the meters as I sang some test passages, and everything stayed in the green, no yellow/red. But when I would play back. louder passages would have a sort of clipped sound, almost as if someone had applied a way too-heavy brick wall compression on it. I had a pad that came with the mic switched on while singing. 
 
Anyway, I found I could remedy this by lowering the gain volume to the point where the green level indicator on the Scarlett barely comes on while singing these sections. The result is that the vocal doesn't have that "overly compressed" or distorted sound, but the result of THAT has been that the levels in the mix have been too low for me to really hear well, even with everything in Sonar's mix control cranked to full volume for the vocal and lowered as much as possible for the music mix. I tried to remedy that by applying input echo, getting the latency low and adding some compressor to the back end in Sonar while singing, and that's helped, but has also brought some other issues into the mix (pardon the pun), i.e., not totally comfortable now with the processed sound of the vocal coming through. I know, nitpickery. 
 
I think a lot of it comes from how I sing certain parts - very loud, very hard, and my songs tend to usually have some pretty big changes in dynamics. I've already done separate tracks for a "softer" verse and a "harder" chorus, so I'm not singing both of these parts on the same track during the same take. 
 
So yeah, maybe there's a technique thing involved that I need to work on, but I do know enough as far as when to back off the mic, get up on the mic, etc. In any case, thank you for all the great replies. I will have some time this afternoon to fool with this some more, but hopefully the above explains my situation a little more clearly. 

There is:

Mic gain on your focusrite. Make sure the levels are right for recording. Check the levels for recording within Sonar! Ignore the levels you hear!

Then....

Gain/trim knob for track in Sonar. Are you making full use of this on playback?

Volume (fader)/for track in Sonar. Generally you keep it around the default setting when recording.

And you have the mic volume for monitoring in mix control IF you are using the zero latency feature.

The levels you record and the levels you monitor whilst recording should be viewed upon separately.

Consider putting a VST compressor into a track for playback purposes along with your reverb effect.

Aaaaaannnddd just one more opinion then I'll shut up.
 
Even though I use the headphone control on the Scarlett I would very much like to have a headphone amp/control. Why? Because right now I am chained to my DAW while tracking. If I wanted to move into the next room to avoid computer fan noise on say an acoustic guit track or just to have a little more room to move around (my studio is tiny) I can't. If I had a headphone thingie then I could just run a cable from the interface to the headphone amp and I'm good to go. Heck even in the studio I have to be much closer to my desk then I want to be and I have to keep my interface front and center instead of tucking it away somewhere a little more convenient.
 
So consider that before sending it back. They are indeed useful for more reasons than just having a level control for your phones.
 
Cheers.

" as I sang some test passages, and everything stayed in the green, no yellow/red. But when I would play back. louder passages would have a sort of clipped sound, almost as if someone had applied a way too-heavy brick wall compression on it."
 
Here seems to be telling the story... If the Scarlett and Sonar do not show clipping yet you GET clipping, this points at something wrong with the mike.