They rejected my bid for the outbound upgrade today.
Really disappointing.

But ExpertFlyer shows 3J and 3C (i.e. 6 business-class seats) available, and in the seat map there are 5 seats that aren't taken yet, so I really hope I'll at least be able to upgrade at check-in...

As for the return flight, the business class cabin is only half full, so I'm confident that the upgrade should clear for that at least...