Thanks everyone for your replies, especially Lbell and Aerospacepilot.

So far there are still 4 open in first and there's two in my party (and we're the only nonrevs), so I'm hopeful. You guys were right though, business filled right up about 48hrs prior to departure. I'm sure the upgrade to first must cost quite a few miles, so I'm hoping there's not going to be many pax willing to spend all those miles. We'll see. I'll definitely go in uniform.

Thanks again for your explanations. I've been playing the nonrev game all my life so I know not to stress over it, I'm just curious to learn UAL's policies.

PS. Lbell911, I understand they don't do double upgrades, but do you know if they had an empty first class, full business and oversold coach, would they upgrade folks from business to first and then guys from coach to business to make room for the oversold coach pax? By upgrade I mean free upgrade, without requiring/offering them to use up their frequent flier miles? Just curious.