Here's what I was remembering - 5 years ago! So long that I forgot that I was the actual OP. 
https://forum.atlas-games.com/t/graduating-class-of-1220-the-anas-equation/1082/1
Not as definitive as I had hoped - now I'm wondering if there was another out there somewhere... 
Edit - for the Long Ritual, here:
https://forum.atlas-games.com/t/how-do-magi-actually-die/5878/9
and
https://forum.atlas-games.com/t/who-gets-the-most-from-the-longevity-ritual/4506/13