Keep in your mind how the nicotine addiction works.
At fist you smoke and trigger the nicotinereceptors, they like it, you'll start smoking. But they'll ask more and more nicotine. They also gonna expand, you'll get more and more nicotine receptors. So you'll need to smoke more and more to have the good feeling.
Anyway, stop smoking with this e-devices is a good start. But! I've you are taking more nicotine you'll have the same effect as with analogs. Now you're still addicted to the nicotine and you did take higher amounts. What happened is what I said above... If you want to e-smoke less, it'll be the same like cutting down analogs. Maybe you can try with nicotine tablets and patches, taking it down over 6 weeks. But keep an regular amount of e-smoking and just use the nicotine patches to get rid of the bad outcomes.
Dear people, keep in mind: Smoking is very bad

But switching to e-smoking just affect health, NOT the addiction... You're still a smoker, you are just using another way to keep the habit and still have a nice amount of nicotine (where you're addicted to). You see, e-smoking is smoking. If you even would decide to quit e-smoking, you'll have all the same problems like if you would stop the analogs. If your not allowed to e-smoking, it's just the same as with analogs. A problem with e-smoking is that you can do it anywhere and it is so nice to do. That's a perfect way keep going the nicotine addiction and you are even making it worse. Try to keep a hand on the nicotine!
I'm sorry to say all of this. But that's whats this all about. Switching to e-smoking is good for the health, only for the health.
anyway,
my advice: make a plan to lower the nicotine amount in a few steps, depends on what amount of nicotine you want to keep. Plan this over 6 weeks or more, at least 6, If you have the time, make it as long as possible. How slower the nicotine drops, how better you'll feel, how bigger the chance you'll have a good outcome. If you want to e-smoke less, start all of this with the time you want to e-smoke and keep this continue (If your lowering in nicotine and start smoking twice at much, it will not the make a difference).
Good luck!