Could you think about merging server 1 and facebook SK.
People signing up on facebook see only around 30 players if that and are obviously not continuing to play. If it was merged with server 1 players might stick around and raise the play numbers.
Also if you added a feature to suggest SK to your friends list this might help get more players. As you know facebook is huge so it would be stupid to miss out on this opportunity. If everyone suggests their friends join with this feature and only 1 signs up and suggests to friends, we could easily get a few hundred or even thousands more players.