I'm glad that you found a setup that you're happy with.
Just so you know, I purchased an inexpensive single coil RDA with adjustable airflow for less than $10 (SMOKTech UDA). I wanted to taste new/steeping juices easily with full flavor. I've tried multiple builds but find that the UDA vapes great between .8 & 1.2 Ohms. All this on my VTR at 15 watts throughout. The VTR WILL fire a full 15 watts as low as .6 Ohms but that's it's extreme and I don't want to push it that hard. It IS a 5amp device. The UDA is a 14mm RDA and sits beautifully on the VTR or an eGo battery (at >1.5 Ohms) for that matter. I've settled on a .9 - 1 ohm build with 28g twisted-Kanthal & cotton. It vapes great between 12 & 15 watts.
While not a "cloud-chasing" setup, in Rip Trippers words, it can chuck clouds pretty well. I think it's the build and the UDA's adjustable airflow. While not a quad-coil Helios setup, even the youngsters at the local B&M were impressed with what it could do when I was tasting some juices.
Just my experience... You CAN drip with darned good flavor, throat hit (TH) and vapor on a TRUE 15 watts. If one could care less about chasing clouds, a good 510 bridgeless atomizer does the trick quite nicely.
Cheers & happy vaping!
~Alden