Im welded front and rear on 60's both steering. With that said I like the weld but I knew what and how it would handle in my rig as I drove a buddys rig with the same package.
You do get alot of plow steer and it does make the power steering run hotter, so add a cooler and expect to make more turns to get around.
But going back to the topic weld VS spool, well a mini spool is pretty cheap but if you have a welder thats cheaper.
If you do weld it just weld the spiders to the side gears, this way if your not happy with it you can cut them out and place another set in, it will suck but can be done, yes I have done that
If you decide you like the welded carrier, then do like I do and add some extra steel to connect the two side gears together, turn that carrier into a nugget of iron and it will last for years.
Oh and phase your U-joints, you got to remember you made a drive shaft out of those two axle shafts, regardless if you have locking hubs or not, those will only unlock the wheel hub but the driver and pass shafts are in one plane/phase.
So if the two sides are not in phase then they bind, its like night and day if you dont phase them, trust me I found that out the hard way to.