This is an excellent in depth description of how the harmonica functions on a technical level and I would definitely encourage those members who are technically inclined to have a look , especially at your conclusion. Adjusting the gap on reeds is a well known part of maintaining harmonicas, especially in the pro world.. and you’ve inspired me to do another video for the tool shed on this topic.
As for tuning, you may have seen this but just in case here is Seydel’s (fine) tuning they use on most harps. It’s called the compromise tuning, where they aim to have melodies and chords sounding equally as musical on the same instrument. This topic of intonation in it self is another big one!
One things I would say is to warn members off using epoxy on their harmonicas though, while I do appreciate your idea of non destructive flattening, unless you’re highly skilled and have a very steady hand too much damage could be done to the harp. Gluing reeds to the reed plate would be a gap too far!! 🙂
Thanks again David, great post!