Just check the awards search function on CX's website. The availability accuracy is high there. Availabilities don't seem to vary between full-redemption and upgrades, to CX they're all awards only. So if you see the full redemption available then it should mean an upgrade is available too.

This award search function is kind of like a gaming app when you jump back and forth between different dates to see when an award would be available, makes you feel like you are playing a round of rock paper scissors each time you click "search"