Which RDA do you have?
I just bought an Igo-S and set it up with a doubled-over 2mm wick and a 5/6 wrap of 32ga Kanthal for use on top of a regular eGo battery. It meters in at 2ohms and vapes quite well. I set this one up for frequent flavor changes, so the wick is fairly short on both sides of the coil.
I'm new to recoiling and had no idea what I'd want. Since I only have eGo batteries, I researched and found 32, 31, or 30ga wire would work well, but there was no clear consensus about wicks. I bought the 32ga from Temco through Ebay.
For wick I just decided to order an assortment of short lengths from one of my regular vendors. I bought 1mm, 1.5, and 2mm. Since the wick that arrived with the Igo-S looked like 3mm, I decided go with the double 2mm option and see what happened. Turns out it works well, and I have no need to change my method or materials for this particular RDA.
If you don't have an RDA yet, the Igo-S seems to be a pretty nice starter. The holes in the posts make it really, really easy to attach the coil. My first attempt at wrapping a coil, while quite ugly, works very well; I attribute that to the ease of working with this atty.