mica as separator
By all means, test away! Just save your sanity and rely on the published results from reliable professionals to guide you. I’m sure the rest of the glass working community would be grateful to hear back about the specifics.
While I’ve read that mica makes a great separator it seems a shame to use it when kiln wash does the job. Good to know you have it on hand in case you run out, though. If you dabble in other art forms (like works on canvas with acrylics and mediums) sounds like you’d have a large palette of choices