There is no 1:1 equivalency unfortunately. For one, not all nic is absorbed from
vape. Also, every
vape delivery system is different. You might have a pod that delivers a very small amount of vapor per puff but at a very high nicotine content. Or, you might have huge plumes of vapor per puff, which yes, will require a LOWER nicotine level.
How much did you smoke per day, what kind of
vaping are you interested in, do you own a setup already and if so what is it. The more information the better but you may have to do some experimenting to find the level that satisfiers YOU.
Yes you can keep it in a cool place. There are no issues with that it's probably the best way to store it, not super bright, not super hot.
Anna
