Hi Rob - I'm too new to send a DM. Can you DM please? I'm looking at the D710 + extra battery and also looking into a Shearwater Teric. Not sure if you do computers too. Thanks!I like the 710, I do not recommend the DC710, at least not yet, for the same reasons already mentioned. It is the 2nd most popular light I sell, perfect for recreational dives. I just sold a bunch to a local safety dive team, they've been very happy so far.
If you'd like to get an Orcatorch light I can save you some money. I can add another 21700 for ~ +$20 or so if that helps. The batteries are pretty good.