I had the same problem then I made one minor change. I know the youtube video shows the guy filling up his V4L cartos from the mouth (white cap) end. This didn't work for me. I would fill it, do the spin, add a few drops more...they just leaked or didn't vape at all.
So the V4L website recommends you fill from the battery end. Ok, I try that using the condom method. I did 11 drops in the clear cover, inserted the battery end in, then 4 drops in the top to moisten the batting. Replaced ring and white cap and VOILA! Works like a charm now. Flavor and vape!