Vaping has some trials and errors and consistency is always a problem. I am no fan of attys and have always loved carttos. I am a truck drive and need to be able to have a long lasting vape without dripping every 5 seconds. Cartos can be a pain in the crack though the problem is when they are being produced there is no exact way for 100% quality control. One little twist or kink in the coil can change the resistance and shipping can always damage cartos.
I have found it is best to use a large carto. I only use SmokTech Xl or XXL dual coil 1.5 - 1.7 ohm resistnace for 3.7 volt vaping -4.5 volt.
If you are using a VV system 4.5 volt -6volt use 3.0ohm resistance.
If you are having problems with flooding use this as a rule of thumb. A new Xl dual coil carto can hold 15 -25 drops.
Note that cartos are not meant to last for weeks but should have no problem lasting 1 week and 2 at the most. I know there are a lot of tricks for cleaning them but this is mostly a wast of time.
Tanks are not tricky at all but you have to remember that if you don't draw evenly and slowly the suction will cause you to suck more liquid than expected into the carto.
Happy vaping!
