I just want to add, that I received my cartos, filled them, got worried for a second that the first could be a dud (very hard pull, squat for vapor, gurgling), remembered posts mentioning running a paper clip down the center tube to the end, and that instantly made it perfect.
It did start to gurgle again though, so it looks like I had filled it too fast (syringe) for such a thick
juice. In my excitement I probably should have done the process in a little longer than 30 seconds from start to finish.
This thing, to quote PBusardo's video review, really is a "beast". I'm very happy with it.