Check out website tiresize.com, you can do all comparisons etc
Personally, I would recommend a 285 / 75 / 16
Read the differences about LT and P and plys.
The 255 85 16 will bebtiny bit taller than most 285 75 16 and of course narrower, but these tall 255 85 will be usually one and half times more expensive since they are not as popular.
The cheapest tire that will require no modification, is as palmerwnd pointed out, the 265 75 16.
See if you can get lucky enough to find a good used tire at 34x10.5 then have one mounted and test fit all four corners.
Donâ€™t forget you will need new spare tire when changing significant tire size