You might try rayon, rather than cotton; cotton is extremely finicky and it's VERY easy to get too much, even if it doesn't seem like too much. Rayon actually wicks a great deal better, and with rayon, you WANT to have a lot, because it doesn't swell when it's soaked, it compresses. Check out the rayon thread, lotta folks in there with 50 lb boxes that will PIF you some if you ask them.
Also, you said you're using at least 50% VG in all your ejuices; that means it's all thick; you might try diluting it just slightly with either distilled water, or grain alcohol (high-proof vodka, everclear, etc). Apparently using alcohol will give a better throat hit, because it has a harsher taste. I use water and it works very well, and really doesn't affect the taste, though it might make the vapor just a bit thinner. Someone suggested to me, starting at 5% dilution, and see how that does, and if it's still too thick, add another 5%, etc. But any ejuice that's more than 40% VG is pretty thick, just because VG is so thick and gummy, and the higher the percentage of VG, the thicker it is and the less efficiently it can be wicked.
Andria
EDIT: Also -- can you post a pic of your current build, with the wick in place? "Too much" and "too little" are really hard to figure out, without seeing it.
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