download.. great job! The ring even looks nice on the light.. very pretty.
It's a pity about the water resistance. To get around that you would have to design something like the Surefire A19 extender, with O-rings at both ends, female and male threads respectively. Either that, or you could bundle a few extra O-rings with your full kits, I would gladly pay a dollar more for a two or three extras.
Great kit as well, I see you have thought of everything, no deanodizing, no nonsense. Interested in one full kit to try depending on price. This is perfect for the ROP.