the over all size of a rim isnt the prob..its just the backspaceing..and a good offset is in my opinion a +38 on, i have 4x4 finders and im runin caddies with a +32 and they rub the bed sides, a +38 would be just right
Caddies are 7.5" with a +31...so if he was running a 7" wheel with the same offset he'd have a 1/4" more clearance from the fender. That would probably tuck just fine.