Well, I just tried this technology for the first time. This is without viewing the DVD, using a PDR light or anything. I just got a used Honda fender, put a dent in it, and went at it with a least aggressive Dominator "head".
VERY interesting guys, VERY interesting. It "walks" the metal with amazingly control. I see very good things with this tool.
By the way, the mandrel needed can be found a "Glit/Gemtex" (click here)
under the "Trim-Kut" line. I am not sure as I type this what size but I removed the grinding disc off mine and screwed on the Dominator Head. It is way to short for my liking but appears to work just fine.
I will post more when more time is spent with it.