If it had a wider moving leaf with a hole in it, it would give you an effective faster speed without actually moving faster. Instead of uncovering the lens it would just pass an aperture over it.
In effect, this is what happens with the little rotary shutter in a Kodak Hawkeye Brownie. A cutout hole in a larger leaf, where larger in this case means a rotating partial disk. I simply used black photo tape to mask the cutout to a smaller size. Trial and error with a shutter speed tester guided the degree of masking required to achieve the speed I wanted.
"Hate is an adolescent term used to stop discussion with people you disagree with. You can do better than that."
—'blanksy', December 13, 2013