833 Assembly Woes...

Realigning the Thrust Washers is My only fear, doing it this way.
I grease the T-washers to the case, and because I assemble it with the face of the box down, they stay in place.
My Left hand doesn't work so well after a Tendon Transfer Surgery...
Oh boy, that'd tough,
Is there enough room to work in there after the Gearset is in, to move the Cluster around?
Yes and no. Yur gonna have to stand her on her nose so you slide the cluster into position and have her stay there. But to do that, from being slid together horizontally, the tail will have to be bolted on upside down with the cluster pin-hole exposed.

The front retainer will have to be removed in most cases, so that the input gear can move ahead tight to the case.
@Oldmanmopar in Post #2, has a pretty good idea, one which I've never tried because I have always been strong enough to drop the back-end in. It might be a good way for you to go. specially since he says;
You don't need much heat we put the bearing in the oven so the heat is uniform.