TSandM:I know you aren't supposed to hot restrike them. But I don't use my backup lights all that often, and I don't usually take them apart and charge them every time I do. So I might use one for ten minutes on one dive, and 15 on another (usually for practice purposes). What I have heard is that, if you do this, you won't get the two hours or so that the battery is rated for, but maybe as little as 20 minutes because the power drain of STRIKING the light is so much greater than the amount required to continue to power it. I don't have this experience, because I don't have a hand-held HID light, but I have read this on line and wondered if you guys had run into it.
I could see this using Alkaline but not NiMh or Lithiums if you are using it as a backup I would recommend the use of lithiums.