GUEST, I got mine from Duane Binkley (I think his name is) at KarenKonnection.org. They have the full one (1963 edition) which I purchased and also some sort of abridgment that's a little cheaper. And they have a (16 Mb) PDF hymnbook you can download, here, but this is text only.

Jack, certainly "melody in the tenor" arrangements are common in some contexts (e.g. Fasola shapenote singing) outside old Scotland. I'll try the tenor line and see what it sounds like. (What I MIDIfied was the soprano part.)

Haruo