Here's what I can tell you...
I used Delta Skymiles this July to fly FREE, BUSINESS CLASS on SAA to Namibia. Now they don't work with SAA anymore.
However, Delta will be flying to S.A. starting in December. I just called in and got three FREE BUSINESS CLASS tickets to go there next July. My wife and I had enough miles to do this.
You need to contact them 331 days ahead of your desired travel date in order to have a good chance at getting the free tickets. I used 120,000 Delta miles per free business class ticket. The crazy thing is: I can't book my return until 331 days before that date. So I have to be up at midnight on October 1 and call then.
If you redeem for this trip, call in and say OVERSEAS travel and then you won't get some "Jabber-Jabber" in India who can't speak English and can't book tickets for beans! And, YES, I am politically INCORRECT!
Too Short