Since you want an auto batt, definitely look at a Generation 2 kit. Generation 2 auto batts have more protection from leaks than the Gen. 1 auto batts, although I wouldn't consider them drip-proof.
Volt from SmokelessImage, Bloog Maxx Fusion, Halo G6, and Smoov would be a perfect fit for you.
The choices at Vapor4Life are great, but keep in mind that they are Gen. 1, so they are a little more prone to death-by-leakage. They do have 10 or 20 second auto shutoffs, which most other models/vendors do not have, so this would be good if you like a long slow draw.
Since you already have a few 510
devices, you could also take a look at the Joye 510, which is available from numerous vendors.