I don't claim to be an expert on the subject but I'm running dual coils with 28 gauge wrapped around a 2.4mm mandrel at resistances ranging from 0.6-1.0 Ohm on a Sigelei 100 Watter. I'm wicking with Koh Gen Do run at wattages from 25 - 50 Watts depending on my mood though I sometimes drop as low as 10 or 11 Watts. I try to square the top of the coils up with the top of the center block and run the coils horizontally centered on the openings in the side. I'm pretty careful with the cotton to make sure that there are airflow paths under and in back of the coil so that both the top and bottom of the coil have air flow paths while the cotton blocks the paths which are not right around the coil..
The side air flow is wide open and centered on the coils while the top air flow is around 1/3 of the way open at 25 Watts or sometimes closed. I open it up wide for Wattages above about 35 and use my drip caps. Normally at 25 Watts and down, I find I get a bit more heat with a standard drip tip so I generally run with them.
I find the best flavor is at 35-45 Watts with my drip caps on though a friend I let borrow one doesn't care for them because he feels he loses flavor. I also try not to get every ounce of air possible through the RDA, I just take slow steady pulls. This gives me a little more density and flavor.
Anyway, those are my experiences and experiments. I don't claim they're anything stellar, just what I've tried that gives me good results.
