As QF isn't a partner of SA Voyager anymore, you won't be able to credit all miles to one program. Obviously SA or CO seem to be the top choice, but with the cheap booking classes you have to go deep into the smallprint.

SA: VS, EK, NZ
CO: EK, VS, QF
UA: EK, NZ
SQ: VS, NZ
US: QF, NZ
SK: QF, NZ
BD: VS, NZ
DL: EK, VS
NH: VS, NZ

SA just released a new program guide but I don't know about the (dis)advantages of SA's program, maybe you get more on this in the "Other ME/African FFP" forum.