I echo jabjo, but am greedier, Alan. Do you have the alternative tunings list for the songs you mentioned at the outset? There was a long article on her in Acoustic Guitar some years ago where Joni Mitchell talked about all the wilder tunings she now does; but it is hard to get info on the famous ones (they never get into the sheet music) -- it sounds as if you have done lots of work on these, which would save some of us oodles of time. Can you enlighten us?
yours, Peter T.