Just booked 2 award J flights for November 2013. For the month I was looking, there were a couple of J seats on most Tuesday and Wednesday SAA flights from JFK/IAD to JNB. On the way down I booked IAD because of the difficulty connecting to a 10:30am JFK flight from ORD (would have required an overnight in NYC). I assume that there's a SFO-JFK p.s. red eye, so that may be a better option for you. IAD departs around 5:30pm.

For the flight back, I booked a Saturday return JNB-IST, IST-ORD on TK. There were 2 seats available right when they first became available; I did not see any JNB-JFK/IAD at that time, and haven't really looked since.

None of the routes through Europe had 2 open J seats, although I hope to grab ORD-FRA-JNB in LH F when it gets closer to departure. FWIW, united.com didn't seem to like my attempts at routing through EZE/GRU, although i suspect you could get that by calling.