Need assistance with nickel

As soon as I started building with kanthal very well, I decided to get a TC device (Sig 75W TC) and now I have to relearn how to build with nickel. I have a Zephyrus RTA and Hastur RDA, and would be building in dual coils. So what I came for, can someone assist me building with nickel (28G)?

I would like to know what resistance I should be aiming for, what diameter, how many wraps, and such. I've also seen a lot of people building spaced coils, is there a way of doing it without a screw?