Those would both look good.
What about doing it in the standard USAF "Vietnam" cammo but replace the "Tan" with deep buff or dark earth to give it more of a SAAF look.
You could also consider using the darker grey on the under surfaces like the Impala Mk2 and Mirage F1AZ's were using at the end of their service.
I did not do these drawings the credits for the origional artist are on the drawings and for this reason I have left the origional captions, titles and badges, I have only modified colour schemes, castles and details to give an idea of what I am suggesting.
Full SAAF markings, fin flash and serial numbers under wings
Darker cammo with full SAAF markings, fin flash and serial numbers under wings (Or variations of markings eg no fin flash etc)
Darker cammo and low viz markings
The Harvard scheme