misdirected baggage

This has probably been asked and answered before, but I can't find it so apologies if it's a repeat...(please don't beat me up - I'm a neophyte).

I'm 1k, have a couple of GPU's and simply want to use them for a round trip in business class to anywhere internationally - (buy economy and upgrade). Is there an easy way to find upgradable inventory, or do I just pick random destinations and attempt to find seats using trial and error on UA's web site? I'd rather not see the GPU's unused and the year is drawing to a close. I'm too tall to play waitlist roulette, so only want to fly with confirmed upgrades in hand. Suggestions are much appreciated!