Ah the good old welded axle threads..................
Chances are if you have to ask about a welded diff on a DD its not for you.
With that being said I ran a welded TTB 35 when my B2 was a DD. Ran 235/75R15 with a welded front and open rear when I started to wheel back in the day. Then went to 31's with a rear locker then 33's then 35's then 4.88 gears then 44 knuckles then 37's all with the same welded 35. But as soon as you weld the front say goodbye to 4x4 at speeds in the snow.
These are the key things that I learned.
Steering, everyone says its a total bitch. Sometimes it can be. It mostly depends on what you wheel and where you wheel it. A short wheel based rig like the B2 the adverse affects are not as predominate as they are in a longer rig with a welded front. Most of the time I could still out turn a lot of the people I wheeled with that had longer rigs with open fronts. This also brings into account where you wheel. My experiences are in the Northern regions of MI. Mainly sand, dirt, mud, snow and some rock. Now say you are in higher traction areas with lots of rock slab and what not. That would make turning harder. How much harder? I don't know I haven't wheeled it before.
Shafts. Good U joints, Spicer 5-760-x, that's all you should ever use. And either run full clips or tack weld the caps in. If you dont do this your shafts WILL NOT SURVIVE!!!!
The stock ford SP pumps suck. Upgrade to a Saginaw pump and run a cooler, this also helped a lot.
Now I run a 60 front with 20" wide AG tires and guess what, the front is welded. I have hydro assist steering because without it steering was hard. Not that it wont turn, it was just hard to turn the wheel. For me a welded front just works, I can still turn just fine, have predictable traction in the front end, and its cheaper then dirt.