This is all good food for thought. I'm sure there are players on this list who could help. For thumb under technique I would look at Valerie Sauvage's videos. I don't play thumb under myself, in fact I find it impossible. A close up video would indeed be helpful. I'll try to do some videos later, although my technique is probably not worth looking at too closely. No matter how many treatises I read on technique, no matter how much sound advice I get from professional players and teachers, I still end up, for better or worse, playing and sounding like me - I'm stuck with me. So maybe I won't be making technique videos, but I hope to help in other areas.
Rob MacKillop -- To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
