Realm will 95% be Golemagg, only when there are multiple hour queues for several days in a row will my guild move to Gehennas.
I tested on Vanilla the mobs we will grind from 1 to ~53, mainly focusing on mob spawns in quieter areas of zones, preferably without quests drawing people there to maximize the chill factor.
We are filling up each and every day. Just added 2 new cleave teams to our roster yesterday who are looking for people to play with. We have 3 teams at the moment that are 1 member from filling. If you are a Warlock, Warrior or Feral you could potentially fill out those 3 teams. For anyone else, be sure to check us out as their are many teams still recruiting on the buildup to Classic.
I also have quite a few duo guys looking for their partners.