18x9.5 +12

I don't know how you plan to run it, but my bump stops are cut down, so it can ride low and also have suspension travel.

My opinion is that you need about an index finger width of room at all the worst case conditions when its sitting in one spot for it not to rub at all. Between tire deflection, suspension deflection due to bushings and everything else, it tends to move around a little bit. Mine has brushed a few times if you take a turn at speed and then hit a bump while doing it. Nothing serious though.