http://www.wowwiki.com/Four_Horsemen_%28original%29
http://www.tentonhammer.com/node/26652

4 bosses: Ragnaros, Meteor, Green Beam and Void Zone:
Raggy puts fire dot on tank, meteor summons meteor (Stack on tank), green beam you gotta avoid chaining :D and void zone you move out of.

Ok enough with the obvious shit; everyone needs Fire Protection pots here, Shadow too but in all liklehood most of the dmg you will take is gonna be fire.

Healing setup:
We are basically goign to have 8 mini 'tank groups', of 1 tank:1 healer. Each tank will be assigned their own individual healer, Meteor and Ragnaros tanks obviously need a paladin for aura and for these healers, the fight is rly easy, just rotate with your tanks. This leaves 4-5 healers who need to take care of the dps groups rotating between thane/mograine and the safe spot. Easiest way to do this, imo is to rotate them between the two bosses and safe spot:

So eg; 2 healers healing DPS on Meteor, will be healing dps on Ragnaros, and one is idle. Then after 2 marks, the healers on Meteor move to Ragnaros, the 2 on Ragnaros move to the safe spot and t he single idle healer, helps heal dps on Meteor.

This is like the tank rotation in that u move between 3 spot: lets say 3 heal groups of 2 healers, (group a), 2 healers (group b) and 1 healer (group c)

Idle - group c
Meteor - group a
Ragnaros - group b

After 2 marks (first 32 seconds)

Idle - group b
Meteor - group c
Ragnaros - group a

Next 2 marks (24seconds later at 0:56)

Idle - group a
Meteor - group b
Ragnaros - group c

So you make a little triangle basically, heres another pro paint job!

If all dps got fire pots for meteor, and they strictly rotate on 2 marks, then minimal healing is required.

Each tank has 1 healer, they will be marked or something, so yeah, you have 12-13 healers in total. 8 will follow tanks, which leaves 4-5 left over.
The MT healers can just follow their tank, and probably should look at the tank thread but we need our best healers for them, the best priests/paladins.

The above picture is mostly for the 4-5 idle healers, who can rotate. If we only have 4, then we will use 2+1+1 split. This is where druids shine as they can hot the current tank too.

Consumables: normal, plus 1-2 SR and 1-2 Greater Fire. Imo its better to use pot cd for major mana pot then protection as you can top your tank and yourself plys maybe spot heal others if u get a chance.