I had that exact same healer comp. I chose to play Disc, although I think Holy would work as well.Reasoning for Disc:
PW: Shield is the only thing saving a player with the debuff from dying in an "oh crap" moment like low hp + slow grip break. PW: B every roll to increase healing from Spirit Link/Paladin while I focus on Dispels. Divine Hymn during last plate (usually 1st amalg pulsing) to remove debuff + provide much needed heals.Reasoning for Holy:
Divine Hymn every roll to clear all debuffs. Straight up throughput - does not require Grace rampup for strong single target heals.
In the end, I went with an SoS/ToT Disc spec. We did not need added damage from Smite/Holy Fire at all, Power Infusion on our Ele Shaman was plenty enough for the tendons. I actually find this fight kind of awkward to play AA/A on now since we stop and go quite often by holding the amalg at ~5% and wait for the grip timer to coincide with the pulsing, thus allowing our dps to purely focus on the tendon when its up. So when I played AA/A on it the past few weeks I kind of sat around trying to get something on a Blood in the meantime. If this is the deal with your group, I would recommend controlled damage on Bloods from you, as you get to plates 2-3 the damage could be lethal from many Bloods dying.
For each pulsing AoE from the amalg we had
1. Aura Mastery (resist)
2. Divine Protection (Prot Pally 4 pc)
Unfortunately for our first kill our OT didn't have 4 pc so we didn't have an additional raid CD from him aside from Rallying.
For each roll we do:
Spirit Link Totem
I took it upon myself to dispel since I can easily glyph for it to heal (Resto Shaman has to spec into it) and since I have 3/3 Mental Agility AND Inner Will up for this fight (its a lot of dispelling!). I do the method in which I continue to dispell Earth until the desired target has it and then allow it to expire so the player gains Blood of Neltharion (damage reduction buff).
My order for getting the damage reduction on players is:
Blood Tank (2 stacks)
Main Tank (at least 1 stack)
Ele Shaman (at least 1 stack)
Rest of raid (at least 1 stack)
Ele Shaman generates a lot of threat from the Bloods since they have such high mana regen. I make it my job to make sure he's safe before focusing on getting the debuff to everyone else. If all goes well and I don't screw up, by the 3rd plate everyone should have 1 stack of Blood of Neltharion with the two tanks have 2 stacks.
Anyways, this was probably way more than you were looking for. I especially liked this guide for the encounter, if you are still shopping around for strategies: http://www.youtube.com/watch?v=Lq_3Tbfzo5k
Hope my rambling helps ^.^