my guitars are dual tracked about 50-70 out (depends on the song). with hard panning, an individual guitar will will sound thin, and the clarity won't be there. when both are played together there sound like there is something missing in the middle.
most commercial recordings the pan usually between 50-90. having the guitar leak an almost unnoticeable amount when your listening through the other speaker, will make a huge difference to the clarity of the main speaker it is coming out of, becuase both speaker playing the same part creates a three dimensional field. when you hard pan. In the stereo field its the equivalent of a band playing live and their amps are put out back in the crowd facing them and a 90 degree angle to where the band is facing when they look at the crowd. In reality they play with both amps separated a fair amount, but still facing the same direction.
its a bad comparison but imagine where your panning the guitars, is where the actual amp is and your listening to it in person, 0 is right in front of you, and 100 is completely to your left or right. you don't listen to your stereo with the speakers like that, why becuase not you can't hear a center, both your ears need to hear the ambiance of the other side, that is why you put speakers of your stereo or your monitors in front of you, not to your sides.
the stereo field as to where the live amp is will really be noticeable with a 5.1 system. if you hard panned, the guitars will sound like they are to your side. take a listen to a commercial song in 5.1, you will notice that the guitars are to your left and right, but they are still in front of you, meaning that they re not hard panned.
but its all preference, you will notice a tone change when you move the panning around. Do what sounds best and always remember where your stuff is standing in the field. or try to imagine where your instrumentation is going to sit in a 180 degree stereo field if your there in person (and emulation of a 5.1 monitor system). just do what works and sounds best, it takes time and experience but you will find what works for you.
hard panning sounds more aggressive but with a thin center
close panning can sound cluttered
i personally like to find the happy medium, and each song is different, so with every song in the mixing process you have to find what works.
