I have business travel to Europe in September coming up and my wife will likely join me. My firm graciously will fund a business ticket, or two economy seats. I've mentioned this before on the board but have more questions.

If my firm were to pay for the two coach seats, I would likely use miles to upgrade us. Its not that many, only around 100k for two both ways. ITs the copay that really gets you. More than 2k USD. You can buy another ticket for that and THEN some.

How do GPUs work? I don't have any because i'm a lowly silver, but my GS father has some and for some reason wants to waste them on me.

Is there a copay associated with these? Once you use the upgrade is it automatic or is there a waitlist?