30 gauge is all I use in my Kanger coil rebuilds! 28 gauge is a little to thick and 32 gauge is a pain to make a nice tight coil, IMO.
I use a 1.4mm micro screwdriver for Kanger single
coils (that's a little smaller then a 1/16th drill bit) and a 2mm for Kanger Dual coils (about a 5/64 bit).
I have a two part blog on how I rebuild Kanger Aerotank/PT3 coils. If you are interested click on the blue "2" next to Blog Entries under my avatar!