I think we spoke about this elsewhere, but it's gonna boil down to personal preferece. You can run 12.50's on stock Canyon/Gambler wheels with 5.5" bs. You can run them with 4.75 or 4" of AR767 bs(they don't come in 4.5", Tech one rockcrawlers do I believe, but don't quote me on that). You can run 8" or 10" wheels, depending on the desired level of looking like you're driving a convertable roller skate. I wouldn't go beyond 4" personally, just too wide of a stance. 4" would keep rubbing to a nonexistant factor, there might be some rubbing at 4.5" (all be it minor). 4.75" will create rubbing at full turn on the lower arms up front. It's doable, I run it. 5.5" is gonna require washers to adjust the front stops and grinding/cutting away some of the upper rear spring perch to avoid slicing a tire. Centering of the axles is also more critical when dealing with a tighter backspacing setup. So a definitive answer, there is none. Sorry.
[b]'00 TJ with some stuff[/b]