I have two gold original Bigsby B3 trems. I bought them to go on PSH-1's ( actually a similar predecessor) and they didn't fit. My poor research entirely.
I have searched for suitable kits to put them on, but all the candidates I considered would be better with a B7, as you'ld need a Towner down pressure bar to get the needed break angle behind the bridge, adding friction to the system.
Long and short of it, I want to make it someone else's problem.
So, if someone wants them for $50.00 each, I'll post em free within Australia I recall paying about $295 each. Duh!