I personally agree on limitation for GB room that kill_em mentioned but with some of my thoughts.
After this event, there'll be tons of BB 6.5 as we all know. Since EBB 6, BB 6.5 and BB 7 are all considered as BB6 and up, I would recommend no more than "4" BB 6 and up per GB room (including BB6, EBB6, BB 6.5 & BB 7) in order to balance the game.