What is the best way to test your juice? I've watch a video on youtube on how to turn a carto into a tester by removing the filler and dropping a few drops along the sides of the wick but that doesnt work so well. I have now been adding liquid to cartos but that seems to be a waste if you need to adjust the flavoring by adding drops. I am using smokeless Image batteries which are kr808 batteries. Its starting to get a little frustrating when you need to make adjustments. I have only used cartos and never used anything else so I'm not that educated with anything other than cartos. Any recommendations on where and what to buy and how they would be used. Any help is greatly appreciated.