Looking for "Standard" awards is the key. (It's a misnomer...the "standard" awards on UA's site are what most of us think of as the 2x-mileage "rulebuster" awards.)

I will usually open two windows if I'm looking to upgrade a paid ticket. One looking for paid W coach seats. One looking for upgradable C seats on the same flight. Right now I'm also poking around looking for one award seat on the same flights as a paid W itin, so I'm pretty sure I need to be seeing XC2 NC2 (or more). I'm guessing that XC1 NC1 wouldn't cut it because if I put one ticket on hold (regardless of whether I start with award or upgrade), that kills the other bucket too. I'm not 100% sure about that though...