Hi. I just got the Smartvapes Smartbox XL bottom feeder as an introduction to bottomfeeders and I must say I am really digging this thing. Currently I am using it with the long batteries I got with my provari 18650 3.7 volts. The Smartvapes site says I can use 26650 batteries with it but they don't offer these batteries for sale. A quick internet search shows me lots of options, too many in fact. Can someone tell me if there's one that I should get or are they pretty much all the same? The only experience I have with changable batteries are with my provari and I just got the ones they sell so I didn't need and don't have any real knowledge about batteries. As such any and all help is greatly appreciated.