here is how I would install the clocking ring. assuming the driveshafts are already unhooked.
-drain the fluid out of the t-case.
-unhook the speedo cable and linkage,
-remove the side support if you still have it (2 large bolts)
-remove the 6 bolts holding the t-case to the adapter, the t-case will not -fall off, it's still held on by the input shaft. it will most likely rotate clockwise down under it's own weight
-remove the t-case,
-rebuild whatever needs it,
-install the clocking ring to the t-case,
while you have the t-case off install your new bushings. having the t-case off give you lots of room to sit under your truck and work instead of laying on your back.
-reinstall the t-case on the back of the trans adapter. it may or may not go easily since there are now studs sticking out.
-install the nuts on the studs.
-reinstall the linkage
-now is the time to remove the spacers from the crossmember, leaving them till last gives you a little extra room to work between the t-case and the floor.
when you raise the crossmember simply support it with a floor jack, loosen the bolts on both sides, remove them from one side and jack up the x-member enough to put shorter bolts in. remove the other side bolts, jack up more and install the new shorter bolts on that side. tighten everything and your down.