I checked the map pool in the client, there's still a small mistake : it has Adaptive Corona, instead of Land Wilderness (according to Ftx thread). Not very important but since I noticed I thought i should notify it here.

You can start playing TMM now! Download link is available in this post: https://forum.faforever.com/topic/854/team-matchmaker-beta-release-now-available

The answer to your question is in the original post. There is no more accurate release scedule yet.