That depends on how wide of a tire you want to run. The stock wheels with stock tires had about 1/8" between the side wall and the knuckle. You may want to run the Type 'B' wheels to leave your tire options open down the road.
Make sure to get your body mounts chopped. I believe almost EVERYONE that runs a 12.50 or wider has to have them chopped or you will rub them.So is that the whole issue with the 6 inch lift kits, is the back spacing more than 4.5 inches will cause the tire to rub on the knuckle? If I go with a 4 inch back spacing I should be good to go with almost any 12.50 width tire?