On the timing, even if availability remains at C0, does AA ever start processing SWUs a few days in advance, similar to complimentary domestic upgrades? If so, then we would have to take that into account as well.
AA starts processing whenever they release seats so it could be a month, a week, or a day in advance, but if AA's algorithm calculates that there's a chance the seat will sell then expect it to go down to the wire.
To your point about checking the seats, I know you can only read so much into this stuff, but as of now the plane appears to be two-thirds full:- 7 of 20 seats in J
- 24 of 28 seats in PE
Just a bit of clarification there. Seats may show available for selection on the flight schedules page, but the seats themselves could be sold and simply unselected by the purchaser which has happened to me a few times. Either use EF or see if seats are still being sold on the AA website/Google Flights. At least there are a lot of PE seats and if you're EXP you may have a good chance for that complimentary upgrade - just make sure they don't accidently use your SWU for Y -> PE though. Good luck!