I think 315/75r16 look just right on a 2" lift.
The biggest problem, in my mind (more than gearing) is that you now have a spare tire issue. It's too big for the stock spare location (a 315 sometimes fits, but looks like your truck has a saggy diaper and the tire will drag on obstacles off road). If you're planning on getting a swing out or if you've got the interior space to store it inside, that's great. But if not, a $2k bumper just to hold a dumb tire feels kinda silly.
Options that fit a little better in the stock spare location: 255/85/16, 295/75/16, 285/75/17. It really sucks that these trucks like to have a full size spare, otherwise, I'd just get a skinny 33 for under the truck and call it good. Instead I bought a skinny 35 (35x10.5x16). Cost a fortune for a spare and it still looks kind of dumb under the bumper.