I posted a discussion on this in the "switching" health forum if you feel you are vaping too much. In the beginning, don't worry so much but it's not as if it's fine for everyone to vape 24/7--it causes me problems now. I'm mentioning the thread for new people because I think there is a tendency for people to think that a 24/7 vape has no effects. If you plan on sporadic vaping like smoking then go high nic, or really low nic for constant vaping. I know your question is more about the carto eqivalent, but, for other new people, it is easy to vape way more than you expect to and you should probably start to get into your future habits now-- sporadic at high or lots at low.