I really enjoy how novel are the alchemical concepts presented, and how mundane the hook of the adventure is(though if I recall correctly, previous versions were a bit more wordy and I felt more evocative). I can totally see myself adapting this to run within any campaign!
If I could point one thing that could be improved it would be having the full letter to Magnolia readable, so it could be used as a handout to the players at the start of the adventure.