I am not that informed when it comes to batteries as I've only had one mod (that had a freak accident). I am between two mods now, one of which is a dual 18650 and the other a single 18650, 20700, or 21700. The ohm resistances would be anywhere from .2 to 1.5. Occasional Sub-Ohm and RDA, but MTL is the main type of tank I use if it matters. I'm new to coil building so unsure if it affects any kind of setup. TL;DR: What are the pros and cons of each setup?