(...) On the dive light I would also suggest not using rechargeable batteries (...)
Could you please elaborate on this point. I was just about to switch to using rechargeables, it seems a bit too much to buy a new $15-20 set of batteries for every dive. I was assuming that a freshly charged set of rechargeables should work better than batteries I already used once on another dive. My 400-lumens LED light claims to deliver 10 hours at max brightness with 8x 5000mAh alkaline C. I was planning to use 2500mAh NiMH rechargeable AAs in plastic AA-to-C adapters. I thought one AA set should be plenty for a single dive, and AAs are cheap and abundant...