Hi Phil!
I'm wondering if you might want to send a copy of iGigBook to some sites like this one ...
https://bettersax.com
I notice that when Jay Metcalf (www.bettersax.com - 8.3 Million YouTube views) reviews a product that the popularity of that product goes up dramatically as long as it gets a good review. I'm sure he'd love iGigBook if he hasn't used it. He recommends iRealBook Pro which I find to be somewhat lame without the melodies to the tunes. He has a lot of followers who could get rid of a lot of paper using your app.
Just a thought to spread the word.
All the best,
RS