One possibility with the bigger shutter is to mount it on a board and get one of those lens chucks aperture thingys to mount on the other side. Then the chuck holds the shutter to the front of your barrel lens. So the shutter's up front, not behind it.
This is certainly a possiblility; I'm looking for something flexible that I can use with my various lens experiments. (which might involve a lot of "thingys")
Tom, on Point Pelee, Canada
Ansel Adams had the Zone System... I'm working on the points system. First I points it here, and then I points it there...