Do you think that when Lyle Ritz worked with Jim Beloff to publish the book, that they intended the music to be played note for note exactly perfect all the time? Or do you think that they might have just published a starting point for you to develop and work on and improvise your own pieces? And does it matter what tuning he used, or is it more important that you just use the tuning you use to develop and work on and improvise your own pieces? For a challenge, set up uke with an open tuning and see if you can make your own arrangement.