Just bought a zap two weeks ago... amazing. Definately only fill it half way the first couple of times you use it to get the flavor going, then you can fill all the way.
For going out an about... I took the foam from the zap packaging and put it in a cup which I place in my cup holder in my car. Keeps it upright when driving. When I get to my destination, I then make my switch to a carto. When I get back into my car, I switch it back. I no longer have the tolerance of the gurgling and leaking of other devices anymore for extended periods of time.
Got a feeling your next purchasse will be PG/VG to dilute your juice. Nic hits like a ton of bricks. I cut my nic in half.
Lastly, I don't find the top cap coming off very easily. Must be an issue of the older zaps. Enjoy!
Ceramic wicks are now on Provape website... just picked up a few. Taste is incredible.