You don't have to get that complicated, folks. My favorite way to connect a flashlight to my helmets involves a 2-inch wide piece of foam pipe insulation (the kind that they use to insulate hot-water pipes - is slit up one side), and a reflective ankle bracelet that closes with a hook-and-loop closure (velcro).
I slip the flashlight into the foam, place it on one of my helmet vents (that face forward -fits great), and then hold it in place with the ankle bracelet (goes around flashlight, and through one vent above where flashlight is sitting). The cushy foam insulation allows you to tighten the ankle bracelet, and you can adjust where the flashlight points a little bit while you are riding, if you get thick-enough pipe insulation.
Last edited by Pinyon; 11-04-10 at 01:48 PM.