Just ordered one of those Harbor Freight "dimmers" to give a try out. Sounds like it'll work great on a Lowel Pro light as a 250W seems to be a bit hot when back lighting a subject in a small area. The color temperature shift won't matter much on the back light as a lot of the time I like to throw a 1/4 CTO gel on anyway to warm things up.
Here's a video you might want to check out that we made real quick to show the difference between using standard overhead lights and then a Lowel DVcreator Kit. That's the Lowel Omni, Tota, and Pro in one small case. Check it out at
http://dvgeartalk.com/