This thread partly inspired me to finally go and refresh my campaign chronicle translation including the arc, handouts, letters and tribunal debate mentioned above.
I've updated my campaign post with the details and link if anyone should be interested.
You can find the alchemy arc near the end (contained within session 89-97 - just search "alchemy", and originating with two handout letters (Ricardus to Guiscard) that are before #79 and #89 (the players were a bit slow on the uptake on this arc, busy with all the other craziness).
Here's a direct link to the first letter that kinda kicks it off:
https://docs.google.com/document/d/10td_pRNap4pv72N06DfB-zCaDwbJ9UIayzjkMqxZI0U/edit#heading=h.4e4bwxm
FWIW: The Handout between session #96 and #97 contain no less than 14 avenues of potential magic and alchemy reconciliation discoveries and breakthroughs that my players (or other magi) may try to pursue if you wanted some ideas on that. To tie it back to the thread, this is what we have intended as more or less potential story events by themselves.