Dan, There were two lenses of the Takumar (Pentax) 6X7 with leaf shutters. - the 90mm and 165mm.
The next camera i make will be similar, but with an internal shutter. That will allow use of the wide angle Takumars i have.
I have just purchased a Copal 495, it is a plate shutter with 45mm opening, powered by a solenoid.
I am about to set the shutter up on a lens bench and measure its performance with a phototransistor and oscilloscope.
I think I can modify it if necessary to speed it up by adding a closing solenoid. I suppose it will be OK if I can get a top speed of 1/100th to 1/125th out of it.
The Takumar 90mm leaf shutter has a speed range, with flash sync, from 1/30 to 1/500.