mycoses, you may be interested in two of my previous threads:
Muse - Brainwave Biofeedback for meditation - anyone using this?
Muse S - Potentially Accurate Tracking of Sleep Stages
As noted in the second thread, I emailed their customer care center asking a couple of questions, and they responded quickly, so you could probably get answers to your questions that way. Common questions and customer care contact info at this link.
~ArthurG