as far as guitar vs bass in volume worries, the guitar will be fine. most every guitar combo will be heard with or over a bass amp/cab setup.
my guitar player had a small 1x12 fender tube combo, loudest thing ive ever heard. i had an 800 watt SWR head, a peavey 4x10 and 2x10 just to keep up with that little 12" combo of his, ridiculous!
my guitar player had a small 1x12 fender tube combo, loudest thing ive ever heard. i had an 800 watt SWR head, a peavey 4x10 and 2x10 just to keep up with that little 12" combo of his, ridiculous!

