Wierd....I tried rebuilding ProTank coils and gave up in frustration. I yielded to pbusardo and Dimitris The Vaping Greek and got a Kayfun because I needed something to use up those materials I invested in for the Protanks......
First coil..Big failure. Second coil.....success.
I don't use cotton, I don't use a micro coil. I simply do a simple 3/4 coil using .34 gauge Kanthal. This equates to approx 1.9 to 2.0 ohms and 2mm Ekowool. I build a basic nest build. Wicks great.. On one coil, I get the occasional dry hit and simply cover the airhole and take two or three hits and that clears it up.
The coils last forever.
I use this build, it's VERY basic, uses too much wick, but works fantastic and best yet, is dang near foolproof. It's not sexy...but it just works....Kind of like the ProVari.
https://www.youtube.com/watch?v=IxFbRfY18VE