This is fascinating. Probably a little explanation for people that don't have music theory experience as this is pretty technical. So possibly instead of C3 + 3. You could do C3 F or something like that. Then your audience just has to match F to F and it works like magic!
Technical stuff: In the browser I was having issues as to where I needed click and drag to get the hexes to move and drag. An indicator could help probably. Overall cool concept and neat take on the theme.