The lyre tunebook is chugging along. I've scored seven 19th-20th century pieces, like "Twinkle, Twinkle" and "Ode to Joy," that people will already be very familiar with. That (in theory) helps them know if they're playing the instrument "right." And I've also scored eight 12th - 16th century tunes (or parts of tunes) to be all medievally. Maybe "scored" is the wrong word. It's just melodies at the moment. I'll be adding some accompaniment separately.
Of course, none of that repertoire is really historically appropriate for the lyre (although the 13th cen. Danish "Dromte mig et drom" is close). But we don't have any 8th century music, period, is my understanding. We start getting chant in the 9th cen.
I may include a section on improvising tunes, and what (I think) is historically plausible, and maybe give a couple of scored examples of my own compositions. I hate doing that, if only because I'm so bad at transcribing what I'm playing into note values. It takes me forever to get it right.