I use 29ga kanthal; 7 wraps around a 7/64 bit, gives me about 1.8 ohm; I put my kayfuns on one or another of my variable wattage mods, and generally stay between 7.5-9.5 watts, depending on how much throat hit I'm looking for at a given moment.
One thing I learned about a kayfun, is that you get a really true taste of whatever's in it; there are some juices I just love, but not in a kayfun; when I can taste some juices that clearly, it's not always a good thing.

I mainly fell in love with the kayfuns for the GREAT throat hit and flavor, and how little trouble they are compared to the small Kanger tanks, none of that oh it's gurgling, oh it's leaking nonsense. The only times mine ever gurgles or leaks is if I get carried away with priming a fresh wick, and have to blow the excess out of the chamber. Still, I'd rather have to blow out excess than taste a dry hit for even one second.
Andria