What wheels are you looking at? Rallyes or otherwise?
15x8 with 4" backspacing like the stock Rallyes/Corvette Rallyes will work with a 255 up front. I was running a 265/75/15 (31x10.5x15) up front even after a 2.5" drop spindle but with stock and sagging springs. No rubbing anywhere. Much lower and I dont think a 31" tire would fit. I am currently running a 235/75/15 with a TON of extra space, so something like a 255/70/15 is a safe bet that it would fit without issue and the extra height will keep you from having the too-small-tire look.
This is my truck with 265/75/15's - 2.5" drop spindle and stock original whooped springs.
Here's with the 235/75/15's which are the same overall height as 255/70/15's (roughly)
I do have a 5/8" spacer in the front to help the 15's with stick on wheel weights clear the drop spindle, but I decided to go 17's ultimately and those are on their way.
I went 17x9 with 4.25" backspacing for the rear and 17x8 with 4.5" backspacing for the front - tire sizes I am unsure of, but probably 275/60/17 in the back and 255/55/17 or 255/60/17 in the front - whatever I can find that either matches or will work well as rear tires and front tires separately.