I'm a bit late to this, but this project is uploaded!  It's already v5.  There were plenty of lessons and changes and fried chips to get to here, but that's a lot to write out.  I (for once) documented a bunch of it in a long google doc: https://docs.google.com/document/d/10RtGc0HOGberA7v5jZShsxAbZBDxf0yVxyILOeaE-VQ/edit?usp=sharing

The versioning is a bit messed up though.  The version at the end of that doc is really somewhere around v3.  Read at your own risk of confusion.

I'm currently working on a few last checks before I get v5 PCBs made, and then I'll test!  Hopefully nothing blows up this time.