I've done a few of them now, and they are so simple. First one I did in my apartment kitchen, the rest I did on an actual trans bench in a shop. Very simple, the only trick is setting up the thrust washers on the front shell, those are still available from Ford though. The rebuild manuals give you a spec, you just pry it forward and backwards to determine the play, and order the color of washer that is the right thickness to bring it into spec.
I have been told that the C6 used in the F250 4x4 from 73-77 had a deeper first gear, but I have never been able to confirm that.