OEM size is ideal, but if you want small increase in height, just enough so it doesn't affect the gearbox and clutch load, you can try the following for comparison
275-70/16 has height/diameter of 31.3inches
265-75/16 has height/diameter of 31.8inches
235-85/16 has height/diameter of 31.9inches
285-75/16 has height/diameter of 32.8inches
The last one probably would put considerably higher load and increase consumption. Also tyre choices will be limited in it.
Finally the speed ratings availability is also limited with non-oem sizes. I recently stayed with 275-70/16 size as that had highest speed rating available (more safety margin)!