Well it worked well on Halloween. We only had a few groups come by but they all seemed to enjoy it. 

Several did it multiple times and since we had plenty of candy it wasn't a problem.

We left a small bucket for everyone to drop the 35mm film canisters into and that worked out well. No one seemed to mind returning them.

A couple of trick or treaters encouraged us to shoot out more then 2 at a time. 5 at a time still worked great. 6 was a bust.