Good question. . . I would think that 30-45 minutes per lesson (which would be once a week) or less would be fine. It would all depend on how much time you wanted to put into it.

One of the things I need to discover is how long it takes for someone to do a particular exercise and feel comfortable, since I'm thinking about presenting this as a workshop, and I'll need to be able to figure out how much time to allow.

Some of the valid bits of feedback will be: "This was too much at one time," or "This wasn't enough."