How low is it? That will play a big factor in wheel fitment. Plus if you want to "move" things around in the engine bay/inner fenders.
I'm dropped 5/6. I have 15x8 rims with -11mm offset. My front tires are 225/60's and the rears are 275/60's. I do have an axle from a Gen II Ranger in it that is 2" shorter then the Gen III. I do rub slightly in the front on dips in the road at speed. I measured the rear last year and was planning on 10" wide rims with 6.5" of backspacing. For your truck, you should be able to do a 10" rim with 7.5" of backspacing. The fronts, people have used 9" wide rims but I'm trying to stay at 8". I like to have a little room to play with.
James