Cage Mounting of Sleeves
The band and using friction to drive motion is not the best. The movement should be more precise than it is now with no lost motion as a band slips around. This should be a "cage" that holds the sleeves like a Quickshot but can be far more open than that. This can then be attached to the handy with a 1/4 turn socket. Most other sleeve type toys dont rely on a band.