I would look at 17 " rims , this has a lot more options available .
basically with the springs in stock location you can get into a 275 wide tire , I have 275 50 for a lower profile
with the springs moved inward you can get into a 305 width , I would get 8 " wide with 15 " , you can put a wider tire in with a 17 " rim as there is lesss sidewall bulge