I like your method, David, and I think that it works pretty well for tunings that are open chords, but does it work for tunings that are not chords? I have tried for years to figure out certain slack key tunings, particularly the one that Gabby Pahinui used on his twelve string for his version of Aloha Oe, with no luck--

I have a book with many Hawaiian steel guitar guitar tunings, and the author points out that it is possible to do about 880 different tunings on a 6 string guitar without repeating pitches--but it is also possible to make drastic changes in string gauges, and to put strings out of octave sequence, so that you have 24 possible pitches for each string--

I used to use a lot of open tunings when I first played. because it made it easy to play melody , and I loved those fat chords with lots of open bass notes--but tuning and retuning is such a chore--