It is amazing the different results we all get with each device. I use CE3s very heavily and have no real leakage issues and they last for quite a long time. I think that a major factor is exactly how we vape. I tend to take long, slow drags from all my devices. My wife, on the other hand, takes multiple very hard drags all the time I loaded some CE3s for her and she couldn't use them...leaked and had little vapor output. Maybe try the long, slow, drag with a CE3. As far as filling them, I use a 5ml or 10ml syringe and mass fill them. 20 to 40 at a time, very quickly.