Hopefully useful feedback...
Hi, as a music teacher, this app would have huge potential if you would consider making the following two updates: first, configure it so it appears full size on all iPads (normal and Pro), and second, allow it to be flipped so it can be used as a traditional circle of 5ths as well as 4ths. I’m sure these would be minor adjustments to make but they would enhance your app’s usability enormously :)