Makes a lot of sense. You take a modal tunng, change the order of the notes to match the order of another modal tuning, and make the pitch higher or lower to match another modal tuning. Once you do all that, you've got equal modal tunings. Insightful, really.

I've found that I rather enjoy playing banjo in an odd open C min tuning - gGCEbG. (Capo on 5, but that's beside the point.)

This tuning is almost the same as open D major on guitar, except to make the guitar equal to the banjo, you'd have to tune down 2 steps and lop off the 1st and 6th strings, then tune the 3rd string down so you have a flatted third instead of the more rounded third you frequently find in major chords.

In any case, this is a great banjo tuning that happened because I was trying to learn a song on it. Currently, I do 0 songs with banjo accompaniment.