Hi jRP. I'm glad you found help here and decided on the V3. I know you'll love it; it's a fantastic device! :)
For batteries, buGG is the battery man too. But I can tell you what he's going to say:
For 3.7v, use the AW Protected 17670 battery that Pure Smoker sells.
For 6v, use AW LiFePo4s...