I can't really add something to the kiter/dps/tanking strategies, although it seems good to me to put ranged in the centre and melee/ranged on the stairs.
The one thing I saw Yed doing and I thought that was really useful is to be walking on the stairs for the kiting, with that making a bigger circle than the strider is actually walking. Logical it seems, because the strider is being slowed down and by the time the kiter moved on in faster tempo the strider will take the shortest way to the kiter ... right through the middle.
For the healing.
In my opinion the healers are assigned to different spots rather than to different persons. You have to be extremely flexible in who you heal. Are you assigned to a spot in the middle you will probably be healing the tanks and people in the middle most. When you're assigned to the outer ring, you'll be healing the elemental dps-ers and the kiters.
Most important thing is that you are responsible for every person that is in range. Sometimes there might be not much to do when there's no forked lightning or kiter nearby. Use the time to either regenerate mana or help the dps with killing the elementals.
So make sure you can quickly change targets and be able to see when a damaged person is in range or not.
You can use the standard-interface for that I'm told, and I'm sure it works just fine.
What I miss in the standard interface is highlighting of dmg-ed persons in range, see who has the aggro and is probable to receive more dmg, or keep track of my HoT's.
The addon I use to improve that is mouse-click-cast based:
Healbothttp://www.wowinterface.com/downloads/info6096-HealBotcontinued.htmlAnother addon that I know of, more customizable, and works as usual select and cast with actionbar:
Gridhttp://www.wowinterface.com/downloads/info5747-Grid.htmlTo reach the same mouse-click-cast effect with Grid or any unitframes, you can use:
Cliquehttp://www.wowinterface.com/downloads/info5108-Clique.htmlNow I'm not telling that you should use an addon for healing, some say that using addons compensates for lack of skills. I only mention the addons because it works best for me.
(If you decide to try one of the addons: I can't help you with Grid, because I don't understand it. I can't help you with Clique, because I never gave it a real try. I can help you with Healbot
)