I'm stuck in the same situation as you. I did my 2.5" HBS now I'm debating on 18's or 20's w/35"ers but everyone I'm talking to says I'll have rubbing issues. I might just go with 33's to avoid the it.:4-dontknow: I'm pretty picky on how my tires and rims are gonna look. DAMNIT. Here's 2 sites to give you some ideas.
I think the biggest thing is getting the right offset. On my 2011 1500 I ran a 18x9 with a 0 offset and it was perfect, but the 2500 has wider axles so a o offset won't work. I need a + offset, but how much? I have been told anywhere from a +10 to a +18. I would like to run a 325/60/18 with about a inch to inch and half out from fender.