It's been a while since I've done this so my memory fails me. I'll be flying HEL-CDG-MIA, where HEL-CDG is AY operated and marketed, CDG-MIA is AA operated and marketed. (Actually, it is an AA award ticket. I do have the AY/Amadeus booking reference for it, though.)

So when should I OLCI to make sure it works as smoothly as possible and I get both BPs? At T36 for HEL-CDG, the AY website probably lets me do it but might leave me without an AA BP. So should I wait until T24 of the CDG-MIA flight, and then check in on AY website? (AA opens their OLCI 24 hours before the flight)