Um, er, ah, why not simply mount your process lens in front of an ex-Polaroid MP-4 Copal #1 shutter? Inexpensive, easily found, timed speeds from 1/1 to 1/125, no fuss, no muss. Vignetting shouldn't be a problem with no movements.
Do it y'rself is well and good, but why settle for an inferior product? Make or improvise the mount adapter y'rself if you must do something.