Depends on the manufacturer of the wheels as how they measure the offset for fitament.
Motorsport Specialties, makers of Halibrand Compomotives has a great web site for this with detailed instructions. They are at
www.usacomp.com
Norris the salesman and Alan the builder of the wheels were great to work with. Not to mention
"They Guarantee Fitament"!
I have an 8.8" rear end, live axel. I have 245/45-17's front on 8" wheels and 285/40-17's rear on 10.5" wheels.
Let us know what you come up with.