Righty tightly, lefty loosey. Have some room to lay out and clean your parts, and it's no big deal. You got he ZF rebuild book?

Some things to kind of plan for include a way to hold the trans case on its tail when removing and then replacing the tower assemblies. Holding the tower assemblies is a pain, and dropping one more so. I made up a clamp with rubber pads.

By far the worst part is R & R the trans itself, at least when yer my age. Taking it apart and rebuilding is not a big deal. But, it is messy. Consider stopping by one of those restaurant supply places and grabbing bus tubs for a few bucks each. They are golden for putting assemblies in and containing all the drips and stuff.