I like a tight draw too and my 2K18 can be closed tight enough for me.I want to get the 2K18 but I like tight draw and I think that bigger air hole (compared to the SXK 2K16) will affect my stile of vaping. I saw that 2K16 base (or even better, the positive post) is compatible with the 2K18 so here is the question, is SXK 2k16 positive post sold separately? I didn't find them on FT tho.