Gotcha. Yeah you basically want them to be moving like they would be outside in a breeze. As long as its not blowing the over 90° against the pot there good. I have mine on the same power strip as the lights...so when the lights are on so are the fans. At night everything shuts down.
I should mention, that those fans are on top of cottage cheese containers which are about 6" high. Bout the best I could improvise. And if I needed them higher, I could just stack cottage cheese containers on top of each other. But they jiggled the plants from that angle.