If you take a mono guitar track and clone it and pan them, you still have mono and no discernible difference or improvement.
 
If you take the time to record 2 unique guitar tracks, even if you do as I do and try to make them as close to each other as possible..... THEN you pan them  there is a very obvious stereo field that will make the guitar sound huge. Depends of course on how wide they are panned. I often pan hard R/L when the guitars will be back in the mix. Things that are closer or louder in the mix get panned a lesser degree. It's all a matter of taste.

if you only took a mono guitar track and cloned it and the took the second track and used the nudge feature to nudge it 2-4 right using sonars default nudge settings it creates a huge sound because even though the guitars are still in phase, they're not quite overlapped, pan these hard left and right. record a second set and pan them to 9oc + 3 oc, these 2 tracks should have a slightly different frequency as well, a smidge higher than the hard L+R's.
this leaves room for the bass to breath in the center and still makes the spectrum acceptable.
solo or accent guitar parts for chorus and such should be over dubs straight up or slightly off centered.
double your guitar leads in the center as to not having them fight for space though with the vocal or bass.
that's straight from the master himself Johny M who taught me everything I know.

Yeah, I clone and pan often. I usually just set the sim and/or other effects/EQ a little different and I get my separation. Haus effect or a slight delay works too.

I tend to use the Haas trick a lot.
 
Pan a mono track hard to one channel, clone it, and pan the copy hard to the opposite side, and nudge the duplicate a few milliseconds.  Alternatively, add a stereo delay to a mono track, and set one channel to have no delay, and the other to have a delay of 1-35ms.
 
If I have two guitar tracks, I pan one hard left, and one hard right, and then use the Haas trick on both of them.
 
Just make sure the delay or nudge is between 1-35ms.   If the delay is more than 35ms, we start to perceive it as two separate sounds.

lol... I misspelled it Haus. HAAS IN THE HAUS, YA'LL! WOOT WOOT!!
 
Okay... that was bad. How does that expression go... I'll get me coat?

When I have 2 acoustic performers, I usually pan their instruments a little harder (farther) than their voices. The less bass in the instrument sound, the farther I'll pan it. If there is a guitar handling bass lines, I'll keep it a little closer in.
 
Also, remember you can send a guitar to two buses and use multi band compressor to center up the bass and pan out the higher sounds of the instrument. That can help give the image of spread while still keeping deeper sounds centered.

I never use Haas. It's mono incompatibility makes it a waste of time I believe.

You can get complicated with panning. One method I like is using 4 guitars and having two crunchy low rhythm parts with a Les Paul style guitar, panned maybe 50:50, then two high parts (very thin and HP filtered) which might be played on more of a Strat style guitar with plenty of high end info and these are panned 100:100. I find this can create a soundstage that almost cups the vocal and cuddles it, if you know what I mean! It doesn't step on it but dances all around it.

Another one I like which is similar to above but uses cloned recordings and an amp sim. Clone the guitar and run through two different sims, one high, one low. Pan the low at 0-50%. Pan the high 50-100% on the same side. Because of the correlation between the two parts, it sounds like one guitar but can still sound thick and wide. Great when you don't want a 'layered' sound. Works well for very snappy rhythmical playing - eg funk style. Layered on that loses feel and edge on each chord due to the layering. It's also great still in mono. Duplicate to the other side with a second recording if you want.

Although there are many variables, I usually pan rhythm guitars about 50-60% Left and Right.  The thing is, although they sound very cool hard left and right, that can sound unnatural.

mattplaysguitar
I never use Haas. It's mono incompatibility makes it a waste of time I believe.

That's a tad extreme, I feel.
 
I would always listen in mono to check for unwanted side effects, as I do whether I'm using the Haas trick or not, but dismissing it entirely seems a little drastic.  Certainly use it carefully, but that is true of most effects or processes.
 
Combfiltering (which I guess is what you're referring to), and loss of high frequencies, when summing to mono, can be easily mitigated by using longer delay times, as they tend to translate better to mono.
 
Don't throw out the baby with the bathwater, though.  It's benefits, such as more realistic panning and fattening tracks panned to extremes, surely mean it is a viable mixing strategy, if used judiciously.  Much like compression.  If used wrongly, it sounds terrible.  If used well, it is just what the track needs.

jb101

mattplaysguitar
I never use Haas. It's mono incompatibility makes it a waste of time I believe.

That's a tad extreme, I feel.
 
 

You're right, probably a little extreme! I only just woke up when I wrote that haha. In most cases I find I prefer other methods. When blended into an original sound subtly you can get away with a bit of stereo haas effect without any real noticeable problems, but if you just do a full on guitar one panned L, shifted guitar panned R, nothing else going on, it usually doesn't work well in mono (and I don't like the stereo sound either as it sounds skewed and one side heavy - like it's twisting your head all weirdly...) if the guitar is the main provider of sound. If it's only in the background adding some subtle articulation or if you're blending it in a wet/dry method subtly, you can make use out of it with minimal artefacts.
 
I just personally don't find a lot of use for it, but I'm not suggesting others shouldn't go for it provided they are aware of its limitations!