I'll often waitlist for first with miles ...but if the waitlist doesn't clear at day 6, and if there's availability in the cabin, I'll cancel my reward request and hope that EUA works.

The catch with that is that you need to put up an incredible fight with the OPSC to prove it was EUA clearing you and not OnePass miles for the upgrade.

I've put-up two such fights this year ...including one where I cancelled my uncleared waitlist 7 days out and had EUA upgrade me at the 5 day window. OSPC needed "proof" that I was cleared by the computer and not by the waitlisting process (which wasn't fun.)

(By the way Continental, when you have Elites willing to throw miles at you for an upgrade, why not clear them? I've "saved" a lot of miles this year on uncleared waitlists that I was more than willing to part miles with for.)