it can be very tough to start with a desired resistance and build to it. when i built my first fused claptons i used 26 kanthal with 34 kanthal, then 24 and 34, then 26 nichrome with 34. nichrome definetly is the better choice as it cut down the ramp up time and decreased resistance, but in my research and expierence, the best bet is to use a nichrome core, the smallest gauge kanthal you can work with on the outter wraps. the number of wraps in the coil and size of ID will depend on your RDA. example, on my Royal Hunter, i usually use 2.5-3mm id with standard builds, but i have to use 2mm or less on it for clapton and twisted builds. your type of mod will also influince your build resistance. you realy just have to play around with it. start big and bring it down to your fit your rda, taste and preferences. good luck.