Skill Based Matchmaking

Anybody have any ideas for skill based matchmaking?

If this platform is going to be taken seriously in the long run, it will need it.

If a game has a maximum of 20 players, you could split them into multiple duplicate worlds. You would have full control over how those players are matched together.
5 Games of 4 Players - FFA, 2v2, or 1v3
4 Games of 5 Players - FFA or 1v4
3 Games of 6 Players(18 Total) - FFA, 3v3, 2v2v2
2 Games of 8…
2 Games of 10…
etc…

Other than that, it would be nice if there was a matchmaking system built into Crayta where you could set a player skill rank and Crayta would attempt to add them to a game that has players with a similar skill level.