I have one bike with that derailleur - the Tommasini - and it uses nine-speed Dura-Ace SL-BS77 bar-end shifters. My other dura-ace bike (RADAC) has the RD-7401 derailleur, same shifters - same compatibility. Indexing works quite well - and both bikes have eight-speed HG clusters. You just lose one shift is all.
Dura-Ace brifters or downtube shifters will work, as long as they're from the same era. I wouldn't bother with the other shifters, though, unless you enjoy tinkering with alternative cable routings.
Shimano Dura-Ace Compatibility