I run mine for 30 minutes on, 30 minutes off. The fog remains for some time and the roots never dry out, they are still dripping wet by the time the fogger kicks on again. I've never had a heat issue, as the device uses an ultrasonic wave, not heat to mag fog. The water is vibrated with an ultra frequency to 3-5 microns. Make sure the fogger you buy has cheap replacement plates. Some of the ceramic plates can be very expensive. My fogger has replacements in a 3 pack for $7.... I've used nothing but fog to root cuttings. I have not tried to feed the cuttings with a fogger as of yet, but intend to on my next clone run.
I'm sub'ed for this thread, as I'm extremely interested in what they can do. I have seen aeroponic channels with foggers at the end that keep a fog in the channel with the roots between waterings. People are loving the results with the roots.