Producing clouds isn't solely based on the RDA, but on the build, and power going to the coil. The Velocity (standard and mini) are excellent cloudchasing RDAs, and a SnowWolf is more than enough to power damn near anything thrown at it. So I would have to say your problem probably stems from the build you're using.
A very simple but efficient build would be a dual coil 8 wrap of 24g Kanthal. It's as basic as it gets, but still produces a lot of vapor. Give that a try, start at around 30W and keep bumping it up as much as you need until you reach your sweet spot. Also try adjusting your airflow to better suit your needs, completely open airflow isn't always best.
This is another example of a stupid easy, fool-proof build, Quad coil spaced 5 wrap of 20g Kanthal, it's neither optimized for clouds or flavor, but does both pretty darn well