This is what I've been using in my Pro-tank Coil rebuilds with a microcoil. I found that it was difficult for me to get the thickness of the cotton right when using cotton ball strands, and they were prone to dry fire or flood. In the Pro-tank application I use a 5/64 drill bit for the coil and (after boiling) use three of the four strands of the Peaches & Cream yarn threaded through (I think this leaves enough room for expansion when soaked.) and another 3 strand piece for the flavor wick. So far no flooding and no dry hits, even when chain vaping. I haven't noticed any drop off in flavor. The consistency is what I like about it most. I've also used it as a wick in my Igo W-4 with a single coil build and it seemed to work fine. But I'm just getting started using an RDA.
http://www.walmart.com/ip/Peaches-Creme-4.70g-Yarn-Ecru/21668263
http://www.walmart.com/ip/Peaches-Creme-4.70g-Yarn-Ecru/21668263