How can I use those product for emg biofeedback? Which designs should I use for relaxation etc.?
There are probably some designs you can purchase or find online. Search for emg bioexplorer designs and I'm sure you will find some. However if you have issues with relaxation and already have a q wiz and bioexplorer you should just train your brain to release the patterns causing you stress and tension. Peripheral biofeedback that works from the bottom up (PNS to CNS) and not from the top down tends to not be as fast and requires much more time and commitment to see the results you would get from neurofeedback. Usually if you train away the faulty patterns in the central nervous system then the peripheral nervous system follows. For example, my problem was anxiety and intuitively you would train to decrease fast activity and use calming protocols usually on the right hemisphere. However after performing an assessment I actually had a slow brain, which I ignored to train because I believed the anxiety was a much bigger problem. After training up faster frequencies in the left hemisphere(front and back) and anterior cingulate region while training down fastwave hypercoherences my anxiety has greatly reduced and my mood has also increased. This was all indicated by an assessment from brain-trainer with a nice report and visuals all included. I do not have any affiliation with brain-trainer, but I highly recommend joining their yahoo group if you are serious about neurofeedback.