jp360cj

The easiest way is if you can figure out how much farther out you want to move the tire than it already is. I'm not sure on the specs of your stock wheels, but most of the previous generation stockers were 7.5" wide with around a +44 offset. Given the same offset, a the outer edge of a 9.5 is 1" farther out than a 7.5" wheel (9.5-7.5)/2 = 1. A +18 offset is 26mm farther out than a +44. That's right at 1 inch (25.4mm in an inch). So if your stock wheels have the same specs, going to a 9.5 inch wide with +18 offset should move the tire out 2 inches.

Havyek

FWIW I am now running LT285/70R17 Duratracs on mine with stock wheels. They sit almost EXACTLY flush with the outside of the fenders.

I actually bought 60mm wheel spacers because I have some 3" fender flares to mount.