Q&A with the Seat Expert

I am looking for a new Alliance. I’m an elite member of oneworld Alliance. I know it inside-out. But they have no network in Africa. I need a global Alliance with a better African network.
Star Alliance offers more but I also need elite membership ASAP. I fly 3 times a year to West Africa(From Florida) and 3 times between West and South Africa. So which Star Alliance member offers me a faster elite membership. Lufthansa or SAA or United.

I’m flying a British Airways 747-400 in WTP. I want to know which is best: 12 B or 12 G and why?