I run 235 60 Hankooks on 7" fronts and 235 60 on 8" rear. They are hotwire wheels. 235 fill the guards out well front and rear. This is at a standard ride height. The only reason they are not 8" on the front is because thats what i got second hand.
Just a problem I had when it was insured with NRMA, no insurance with 8" wheels.
I think I will run 225 on the gts wheels as 235 are probably too big really for a 6" rim.
I had 225 60 on 15" by 7" Simmons wheels on my old wb and it was way lighter in the steering with them on it than the standard wheels it had originally.