contactcr
(contactcr)
2060
1 & 2) The UCL lens works but the bezel has a very slight gap using it. It does improve the tint of the beam though. However, there are cheaper options I suspect: Ask FireFlies directly (ff-light@hotmail.com), they are usually open to selling parts. The other option is to find an (online?) store that sells watch parts. They sell clear glass is any size and thickness you could ever want typically.
3) yes
4) bezel, oring, glass - almost always. There is a groove in the inside of the bezel and that keeps water from coming in the front. There is usually another O ring on the outside body threads that keep water out from the sides.