Thanks, everyone. To clarify…
The fan is http://www.barnlightelectric.com/barn-ceiling-fans/high-velocity-ceiling-fans/60-white-high-performance-barn-and-farm-ceiling-fan.html?sef_rewrite=1
I got this because, while not beautiful, puts out huge air velocity. It has no mechanical speed control; just the GE fan speed switch. At high, the fan runs at what must be full volume because I can’t imagine the fan going any faster without tearing loose from the ceiling. 
The slower speeds seem to be controlled by the GE switch. It doesn’t matter whether I go to the low or med settings via the wall switch, DTH or a SmartApp (e.g. CoRE).
My estimate of low=10% and med=20% is just a subjective guess, but it’s darn close. At the medium speed, I would guess the rotation is just less than 1 revolution per second. At high, there is no way to measure without a high-speed camera. My wife won’t sit under it.
What I’d really like is a fan speed controller (ST integrated) that has finer granularity of speed. Or, the GE giving something close to 33% and 66%.