Running 1.5 to 2 deg neg camber is going to wear those tires out pretty quickly on the inside. You are correct that autocrossers may use that high of a number, but they aren't worried about tire wear. Also raising the front end 1" over stock may lead to some handling issues.

I am running 17x8 wheels with 4.5" backspacing myself. I have 225/505/17 up front. My front end is actually lowered from stock. I had a slight rub at the bottom of the wheel well on one of the bolt heads holding the inner fender to the outer. This was only apparent after I added more caster. I think I got to about 2.7deg of caster. I just removed the bolt and replaced with a button head bolt and all was well.

If you're just rubbing on the fender lip, you can have them rolled.