CX has proven unreliable on their JNB//HKG service schedule. A few months ago they were showing a 744 with F 4x week for the summer, then it changed to 3x a week. Then, a month or so ago they dropped that altogether and showed no F product on that route from mid-April through October. Now, they're showing a Wed-only F available on the 343 for that route.

My point is, I wouldn't keep your hopes up. (Northern Hemisphere) Summer F offerings on that route seems to change once a month. Unfortunately, the only other choice is JNB//SYD but that too only has F 5x or 6x week and has had some reliability issues. It would also bump you to an AONE5 instead of AONE4.