OK, round #3 with this thing...
Removed the springs and assembled the unit with a single 0.020" shim. Burnished the clutches 20 turns in each direction by setting a wheel/tire on the floor, sticking an axle in the hub, placing the diff on the axle, sticking the other axle in the diff, then another wheel/tire on that axle, then round and round she goes! This was easy with little resistance. Added another 0.020" shim and it would not budge. Removed that shim and added an 0.013" shim (where I was originally). This was about like the resistance in the Tom's vid with the exception of one tight spot for about 30° of rotation. After making 20 rounds in each direction, things got no better, so I assembled the diff with 0.033" shims and the tight spot. When I was seating the ring gear, it seemed to want to "break away" and rotate around 45 ft-lbs again. My shoulder quit before I did, so it's waiting on a "mood adjustment" to torque the ring gear bolts and reassemble it. Is this as good as it'll get?
One thing I did ponder on, the thrust washer just "floats" until the clutch pack wears enough for the clearance to disappear, correct?