Single coil Rebuildable are generally the choice of flavor chasers. If you want more clouds you should shoot for anything with more coil surface area. 2 coils can produce more vapor then one.
....Very vague answer.. not quite the correct answer especially in the context of the original posters question on the tank atomizer. Currently, my .5 ohm dual coil build @30w is not producing as much clouds as my .5 ohm single coil clapton build @ 25w.
For my answer to his post, it mainly depends on the build deck and what kind of coils you can put in. Although the ammit can support a fairly beefy single coil, the coil is limited in space because it's 22mm. It's probably going to offer the largest coil possible at 22mm. I'd guess you could even wrap a clapton around a 3mm or 3.5mm base and still have room to spare..
All that guessing about the ammit is based purely on what I've seen. I would wait to hear from someone who actually owns one and can tell you first hand how it performs.