thanks for the replies. looks like HKG-JNB and SYD-JNB are going to be difficult to get in U, but I will give both a shot at 300 days in advance and see what I come up with.

Two questions - are X tickets typically available on these routes (book now and hope U becomes available)?

Outside of leaving JNB and South Africa out of my itinerary, any other ideas for getting award tickets from SE Asia to JNB or southern Africa [I guess I could go BKK-LHR-JNB, assuming I could get a LHR-JNB BA flight]?