If you are looking to play offroad, your current wheel and tire combination seems an odd choice. With better footing under you, there is a lot you can do on 31's or 32's in a Dana 35/30 setup and no lockers.
If you have a Dana 44 in the rear, you can modify your Jeep and comfortably run 33 to 35 inch rubber. At the larger end, you can reasonably expect the need someday to upgrade to higher quality axleshafts. Lot of locker options available for the 44.
Some people wheel conservatively on 33's running a Dana 35 out back. There are upgrade kits for it making big strength claims, but the general consensus is that it has a weaknesses: ring and pinion, 27 spline axle shafts, C-clip design.
The Dana 30 up front usually withstands bigger rubber and a traction device, but stronger shafts are a good idea.