Now that the epoxy clay has dried, I took a look at the Heli-roc. I had reinforced the thin plastic hinges, which hold the heliocopter blades, with epoxy clat because they seemed very flimsy. I didn't think they could survive the shock of being pulled open by the rubber bands.
Now, with the epoxy clay, they're much stronger. I successfully strung all three with their rubber bands, and they survived several simulated openings, though I do need to reinforce the stop blocks with epoxy of wood glue.
While I had the blades strung, I also performed the recommended test to make sure the blades are properly tilted. I placed it on a dowel and turned my ceiling fan on to 'high', and sure enough, it spun just like it's supposed to. That means that, assuming it survives the forces of flight, it likely will spin down slowly like it's designed to.
The motor hook on the Multi-Goon is now reinforced; building is done, and it's ready for painting.