I used Dexron III - which is backward compatible with Dexron II. Lots cheaper than synthetic ($2.86/quart (Napa)).

By the way: the Haynes manual lists 6.3 quarts are needed for a drain-and-refill. But as I changed filter also (hence took the pan off) and all atf was also lost from radiator, hoses, etc - I needed 10 quarts (and dipstick still shows slightly low).

Does anybody happen to know the official amount when filled from completely empty?

I can report that the $25 Autozone atf filter T722 fits well and includes 2 gaskets. Not difficult, just a lot of bolts (and a lot of atf dripping).