So a question for the rest of Jan and Feb for someone already EXP.

My thought is to be booking, checking in and entering lounge etc as AA EXP but then switch FF on the booking to whomever credits the most miles on a per-flight and per-class basis.

Does this make sense? There's nowhere else to go in AAdvantage, I don't need the miles and could use them elsewhere and I don't hate the idea of status in another program as backup.

If so, when and how to change based on others experience? Can you still change online on eg Finnair site after checking in or does it need to be at the Gate?

Any advice appreciated!