Actually my plan was to make this system 100% compatible with incompatible lobbies => real room would be created with temporary setup and map set to map that is about to be started. It would be started as normal too.
But such candidate room might be destroyed/changed in the process (for example too many players leave -> need to merge 2 "candidates") thats why i only wanted option to move users around..
I would move them between candidate rooms and no other lobby changes are needed.
Lobby protocol - move player from battle to battle - Page 3
For the discussion of infrastructure improvements and changes.