Craig - You're right of course. By the way, that suggestion does work on occasions where it seems like latency is happening when you don't expect it.

Charles, okay, a bit more detail:
 
Scarlett MixControl.  Mix 1 Tab.  Leftmost channel (Analog 1/2 In). Let's say you've got a microphone plugged into 1.
Routing under sliders: Mix1 L to Monitor Output 1, Mix1 R to Monitor Output 2
Input buttons at bottom set to Line (not Instrument). 
 
Settings button at bottom of Mix Control - set to 2.0 ms if you can do that.
 
In Sonar Platinum have an audio track ready to record your microphone. Let's call this track Vox1.
 
Also have that Vox1 track with an output to a bus.  Let's call that bus "Vox" and have that Vox bus point to a Master bus.
 
Set up an additional bus called (for example): Live Monitor.
 
Here's a tip (what I do).  Actually have two Live buses.  One called Live Monitor, one called Live Verb.  Each of those buses should route to the Master bus.
 
Having two allows you to definitely increase the volume of what you're tracking/recording (put it in the front of the mix in your headphones) and also allows very easy balancing of how much verb you want in your ear.
 
On the Live Verb bus add a Verb effect, set to 100% wet. 
 
On the Vox1 track, first you have your track output going to the Vox bus.
second, you add a Send on that track to Live Monitor (which is your dry monitor, allows you to add volume)
third, add a second Send on the Vox1 track to the Live Verb bus.
 
Turn the input monitor only on the Vox1 track.
 
Turn on the Sends on for Vox1.  They start at 100%, but you can move the send volume down.
 
You can reduce the Live Verb send to much less than the Live Monitor send and you'll have a light reverb touch, or you can increase it.
 
Alternatively, you can just have one Live Monitor send (with the reverb on it).  But I've found having two makes setting the adjustment of how much reverb and the overall monitor volume for that track super easy to control.
 
When playing back the track after recording it, simply turn off the Sends and you'll hear the track as it should play at normal volume without the "live" bus reverb.
 
Personally, I like bringing to the forefront in my headphones the monitor volume of the track I'm recording (leaving the rest of the song at a lower volume)
 
 
 

lawajava - Thanks for taking the time!! I'll have to wait til tomorrow to set it up & test. You didn't mention muting the vox1 so it sounds like that's not necessary. Not sure what happened when i tried but I'll have more time to test it out tomorrow. thanks again!

I'm up & running. One send is enough for me so it's easier. Thanks again.

Funny how the latency delay can actually be used to fool a client. 
I normally track trough my Yamaha 01v so adding reverb to the headphones is easy. 
The 01v is getting old and someday it just has to die.. 
So I picked up a little Mackie Mix 8, a Joe Meek ThreeQ pre amp and a Lexicon MX200 reverb/Delay unit. 
A client showed up as I was just getting this new system all hooked up and I didn't have time to test. 
The reverb wasn't working ( later found a dead cable) and he was asking for his reverb on the headphones. When I engaged input echo the latency delay came through as well as the reverb on the send already in place . He went , "thanks that sound good"!!! You can adjust the amount by turning down the tracks volume. Of course that does not effect the record level.
There's no real need to fuss as much as described above. Just turn on input echo, turn down the track volume but crank up the send and return of the reverb buss. This makes for an all wet signal so the small amount of delay is burred in the reverb and you won't hear it. Your basically turning down the dry signal and cranking the wet. 
 
Anyhow most cheap little mixers come with reverb and it works without any fuss. I bought the Lexicon for live performance but it's pretty nice to use that kind of quality just for tracking.