By the way, apart from the historical evidence matter, double frets are very, very nice to use on lutes. I've had some trouble getting a double-strand tied tight enough in the past, but I really like Sean's idea of using independent frets side-by-side. This makes them easy to tie and allows one to change only the worn one when needed, as well as allowing one to choose slightly smaller upstream frets in the pair. MT, I would second the recommendation that you give them a try.
-Peter -- ___________________________________________________________ Sign-up for Ads Free at Mail.com http://promo.mail.com/adsfreejump.htm -- To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html