I've only got 415, I'm afraid.
I guess you don't get very high in the end by playing half your games with the same team
I think most of my teammates for this medal came a while ago when I used to create 50 World 2.1 quads or trips and just let whoever join. I don't do it anymore, because the only thing that happens now that you can reserve spots for people is that organized teams join the other side, which makes the whole thing rather hopeless.
Actually, pretty sure I've played games with or against almost everyone of you at one point. And about 100+ with or against TTN.