Quick wheel offset Help! 1992 Base

I need help here, I've searched and searched, but haven't found the answer for my generation 3000gt. What is the proper (or min and max) offset for a base 1992 3000gt? The wheels are 18 X 7.5 ROH Adrenalin's and I think I'm having problems with offset but I'm not sure, brakes are grinding a bit I think.

Any help would be appreciated!