tire size 01 f350 dually

[pwrstrkdsl7.3L]

Im putting on a leveling kit on my 2001 f350 dually I currently have 235/85/16's i was wondering with this leveling kit what i would be able to get away with all the way around looking to go bigger and beefier.
and any reccomendations on tires.
I currently have cooper discoverers at3's. im lucky to get 25k out of tires ive tried the bfg comm t/a's. and they havent done to well about 20K per set, and im at 15K on my AT3s and their about 60% tread.

[Bionic4.0]

I run a 265/75/16 on a stock height 4x2 with out rubbing. I have to keep rear pressure up close to max but still have room between tires. I do have a slip on spacer(not sure of size, again slip on not bolt on.) i want to add a bolt on spacer and level kit to front and go up to 285's maybe but defiantly want a bolt on spacer and level kit.

also with tire brand i have seen good luck out of some freinds trucks with Toyo open country M/T or Nitto Terra grappler the Nitto were noisy but lasted a while.