Ok, so I'm going to buy 7 tires (6 plus spare). I have seen a couple threads about the 16.00r20 having clearance/fit problems on the 5 ton . If I'm not transporting heavy loads (i.e. not causing suspension to sag down) will they fit without modification? I'll try to find some threads on the subject but feedback here is appreciated. My understanding is the 16.00 can go on the same wheels.
EDITED TO ADD: Is there an advantage to running HEMTT rims on the fronts (or all positions? I read something about that but didnt understand it.
Unless you articulate the suspension pretty severely, 16.00s won't contact the bed no matter how heavily you load it. Off road with the suspension all twisted up and they'll contact even with the bed empty. On road, you can load the truck as heavily as you like and you can't make them touch.
You can alter the bump stops to limit articulation to keep them from ever hitting the bed, or put a spacer between the bed and the frame. (FWIW, your 14.00s will also hit the bed under the right conditions. It takes a lot.)
Steering travel adjustments or hemtt rims are required to prevent tire rub with 16.00s on the left front. My preference is hemtt rims all around.
I have not seen CTIS retained while using hemtt rims, but it should not be terribly difficult to do.
I have 16.00s and HEMTT rims on my M925 pictured. I like them a lot and they're my first choice for this truck and the way I use it.