Another Ukulele player here currently using a 13" iPad Pro as a music book.
I wonder if either of you could try loading Jim's Ukulele Songbook (
http://ozbcoz.com/songbooks/) which is a large pdf (over 2000 Pages) with live index links to the songs in the contents page.
Navigation on the iPad is pretty good, but I wonder if it is acceptable on eink bearing in mind we do not have a lot of time in between songs to find the next.