I purchased my Schacht combs up at the "Studio 66 Retreat" (May 2011)
The vender was Weaver's Cupboard, Gail M. Marlow-Kickey
8287 Calle del Prado
Rancho Cucamonga, CA 91730
I found this video on how to use these. There are two different kinds that I saw, one set was narrower and wider with finer "teeth". The other the one is for wool and is shorter and the teeth courser.
When one of the ladies showed me how to make "rollags" the key was to pet like you would a kitten as opposed to stabbing.