I would say less than 10, and the rest are filled into th tank with a needle and left it there for about 10 mins before vaping.
The first one which I ordered was fine (the one which came with the tank and drip tip), and I did the same exact refiling method with the replacements and they leak.
Quite unhappy with this experience, as in a box of five, THREE leaked. If only one had problem, I would probably think of it as a lemon. But THREE out of five? Worse still, the connection part of my battery was often flooded as a result of this.
haven't tried out the other two new boxes (will do so soon) and honestly speaking my hopes of 3/4 of them working, about 7 of 10, are low.
Will try a carto each from the two boxes later on and update you.