15 x 8 will look fine. There is one member on here running 33 x 12.50 on a 6" rim to try and keep it as close to flush as possible. His ballons a little bit but nothing that catches the eye. He has had that set up for around 5 years with BFG A/T KO's and the tires need to be replaced because of dry rot, not tread wear. Every truck is different, but playing with the air pressure until you find a happy medium is the way to go. I was in the tire industry for many years and have seen it all. But in my opinion, 33 or 35 X 12.50 on an 8" rim looks way better than a 10" rim. The tens give it a stretched look, and as stated above, unless you are running bead locks there is a geater probability of popping a bead in extreme circumstances.
