Thanks for the detailed reply, Seb.
I'm quite curious how the O2ptima will do in the market.
Andrew, I agree that Lamar's accident was an important event - an important reminder to watch your hydration and make sure your body is up to speed when you go diving.
I seriously doubt that being on a rebreather or that particular unit had anything to do with it.
Actually it should have been helpful as it means hgh O2 percentage in shallow water and avalability of pure O2 (or almost pure) as of 6msw until medical attention could be given.