I use drippers & rebuidable tanks. I'm not really experienced in subtanks except the cubis which i bought about a month ago. It compares favorably with my favorite RTAs. Surprising. It cost 19usd, in America. Using 1st coil,,1ohm for 3 weeks about an hour/day.
Nickel just tastes bad to me. Titanium could have issues with emissions. Keep temps reasonable. I like kanthal, but can't use in TC. This leaves SS, may be used in TC or power mode. SS316 is an ideal wire..