I understand. But the only way ive found what works best is by experimenting.
Speaking of experimenting, I just wound a 2mm 20ga Kanthal coil on my kayfun. I was a little leary of smaller wick diameter, but it turned out just fine. I'm getting great flavor and more vapor at 10W without any undue heat in the vape.
I always thought that a 3mm coil didn't contact enough wick to be optimum. 2mm is almost twice as wide (14 wraps) as my old 3mm coils (8 wraps).