Guess it depends on your division, but after 4 weeks I won a couple GAs, and the other two I lost 1 round. Once by 1 point (ouch) and once by 7 points. I just hit Kyber with the last GA win reward, which seems reasonable. If I won everything then I'd be in by a couple thousand points, and I did a few of the feats (not all the arena ones, or undersize squads).
Sadly I can't see now though - I have no GA icon/access any more today??? :(
I'd like to have rewards for close games, as 1000 for a win vs 0 for a loss in a match decided by only 1 point sucks (that can just be RNG). Love to see a 700/300 split for games under 10 points or something.