http://www.e-cigarette-forum.com/fo...zer-systems/499201-mech-rba-useful-links.html
1. Battery safety required
2. Just try it and see if you like it.
I haven't yet twisted any wire, but I don't think it works exactly like a dual coil, halving your resistance. I would guess maybe 5 wraps instead of 4 twisted might get you around .5 ohms. Assuming same coil diameter and guage wire. You can always start with more wraps and take them off as you like. Only one real way to find out though...
Edit: Thought about it a little more. Using two strands of wire instead of one should cut your resistance in half, similar to a dual coil. The difference is that twisting the strands around each other should mean you're using more wire in each wrap, so I would think you'd need less wraps not more to achieve your desired resistance.
Anyways, I hope you can see, I'm really just guessing here and that you'll pretty much have to figure it out yourself,
through some trial and error with different builds.