I had to stop and laugh multiple times while reading. Using Brindlewood Bay’s mystery solving mechanic for a solo game is a really great idea!
As someone already familiar with BB’s mechanics I got it right away, but re-reading it with your goals in mind I might suggest taking another pass at the self-diagnosis section. The sentences have a lot of clauses and sub clauses and are fun, but not entirely clear to the uninitiated. This is the most important mechanic and so I might try to strip it back to something that explicitly tells the reader “this is how you win the game”. Pure technical writing. maybe even an example if you have space?