I used 30 for Pro
tanks, then moved to KFL's. 30 didn't do the job in KFLs, I think because the coils were too fragile and I wanted a bit more power. Did try 26 briefly but that didn't work either, can't even remember why. That's 6 wraps at 2.5 which comes out around 1.10 ohms. Vape it in power mode at 12W. Perfect MTL vape for me. Never did experiment much.
I kept a diary for years after I started
vaping. I just read through the entries for the time when I started making coils 28g coils for the KFL. By chance the first coil was perfect. After that it took around 20 coils before I could consistently make good ones. Do it in my sleep now.