V2 is a KR808D-1 with overpriced parts. You should also be able to use cartomizers from Vapor4Life, Bloogplanet, SmokelessImage and Halocigs G6. KR808D-1 is the most popular 2-piece. V2 just is not the most popular vendor. They also exaggerate about their batteries being 4.2v. All KR808D-1 and 3.7v batteries are 4.2v unloaded fresh off the charger. But they are called 3.7v batteries, not 4.2v.
With a KR808D-1 manual battery you can use a standard resistance DSE901 atomizer and drip tip (LiteCigUSA.net has them) to test eliquids. If the drip tip is plstic or delrin, you can also use it as a comfortable and easy to remove mouthpiece on the end of the cartomizer instead of the endcap. If you add liquid to your cartomizers, be extremely careful if you have automatic batteries (autos are most easily damaged or killed by juice leaks). Always take the carto OFF the battery before add liquid and make sure it is not going to leak before putting it on the battery.
Ego-T too? You are jumping in with both feet! now you have the two most popular threadings. Did you order eliquid? Newbs are the ones who get caught short on liquid. I hate to see that.
As accessories for Ego T I recommend a standard 510 atomizer and 510 drip tip (the ones I mentioned above are 510/901/KR808D-1) for testing juices and dripping. And learn to use Boge cartomizers (the simplest and most popular cartomizers and I use thin juices with cartos - a couple of Vapor4Life WOW juices and other juices that are PG w/ 20% or less VG). The cartps will be a great backup to the tank attys/tanks and are good for flavors you want to keep totally separate. I can get about 10 days use out of a Boge carto but you have to keep cartos damp or they will singe. I fills blanks with 18+ drops, clean it up, let it settle on different sides for 15-20 minutes and then just vape it and keep it damp.
Tanks - I think they like 30% or less VG though some 50/50 juices may work. PG is thin and lets through the most flavor, nicotine Th and nicotine irritation. VG is thick and dulls/smooths everything PG lets through but adds thicker visible vapor.
BTW VaporSearchUSA.com will help you find any local shops