[samibe]

I'm an organist as well and have been trying to find a good option for several years. The facial gestures are nice but I don't want to take the hit in battery life. My current workaround is to use two-page display and single page turns. If I can find a spot on the right page where I can free up a hand (a rest or close chord), I can use my free hand to turn the page. It works reasonably well if the music I'm playing isn't too crazy.
I've tried a few shutter buttons. The cheap ones trigger a volume up or down button press. Which isn't great if you're using the metronome or a backing track. I don't know if there are any that can be reprogrammed to some other input command.
I've wanted to try the Flic button but I'm not certain that it's compatible with my devices. The Flic button would work just like a piston and could probably be temporarily attached to the piston rail with something like sticky tack. Historically, the Flic button has only worked with iOS and Forescore. I have no idea if (or how well) it would work with MobileSheets and other operating systems.