Well I found that the smaller diameter wicks instead of the bigger fat single double wicks are more key, when I rebuild my vision vivi nova heads I am using the .6mm or .8mm wicks in bundle, tried 2.5mm in 2 peices and they werent good even making room for them, I figured out that I was getting alot more flavor on my 1.8ohm Vivi heads and noticed they were all the small diameter long wicks so my thoughts are small diameter and am using them long which I don't think is the key but your opinion might vary