After a while searching for an upgrade for my now rusty, and scratched istick I believe I should upgrade to the evic VTC mini 75w with the tron tank, however, I can't settle on which battery to buy, also what I should know before getting in the world of sub-ohm vaping. I have read one too many horror stories, so I don't want to buy it without knowing the potential risks (assuming there are any). Any tips on proper use of the device are welcome.