I don't see any issue-- in fact, if you approach the agents and sound like you know the process (don't board right away; give them space to work) they may be more inclined to use you, even.

I would hold to the addage that the first to volunteer are the first to be bumped-- regardless of what you did yesterday.

If you must get to Europe tomorrow, I would suggest you check out itn and schedules to build a few back-up options (i.e. if I'm bumped from this flight, can you put me on flight XX connecting to YY that leaves in 45 min?)

A note about CO bumps: I believe each voucher can only be used for a single ticket-- so the $700 can't be used for 3- $250 tickets, but for one single itinerary. (Note there are different interpretations of 'single itinerary'.) Regardless, something to keep in mind.

Have a good night!! Get to the gate early tomorrow to volunteer!