Originally Posted by JJeffrey

No no. J is full fare business class, U is award space (sAAver business), and C can be upgrade space or a revenue business class fare bucket.

C space is what you need for an SWU upgrade, BUT you must search ExpertFlyer using the "Awards and Upgrades" section to see the correct C space. If you search using the "Flight Availability" function then any C space you see doesn't correlate to upgrades. I'd be shocked if an AA metal flight to SYD is actually C7.