I go to South Africa once or twice a year and have booked my wife and kids at various times on points. In F, only thing I have seen is LH, which opens up 10 days or so out. I have flown in J on SA, LH, Austrian and TK. Most often J routes seen are YYZ-IAD-JNB on SA and YYZ-GRU-JNB on AC and SA. I have also seen TK, Austrian, and L H quite often. Through Europe you usually get a full day layover in either IST, MUC, FRA ot LHR. Austrian and TK go to CPT direct, avoiding the JNB connection if that is whee you are headed. With Austrian you can also avoid the long layover.