I may help you with this (I've done heroic 10man 6/7 pre-nerf).

I only used non-A/AA spec on Baleroc, the rest was done either with A/AA or Holy. A quick rundown:

Shannox: any spec works with no real benefit of AA;
Bethtilac: I was sent up and the 15% boost from AA helped keep people alive there as well as during acid rain she does after Devastation. AA is also great boost on p2, especially combined with Power infusion/BL;
Alysrazor: AA is at its best. It helps tanks with dps on the birds and the 15% boost to healing in the AoE phase is perfect;
Ryolith: I was holy on this one, but AA can utilize increased dmg taken by the Spark to heal the tank and help with DPS. 15% boost for p2 should also be considerable;
Baleroc: no AA here unless its long on farm. Shield the tank prior to each hit of Decimation blade is huge and absorbs about 1/3 of it. Also, very high single-target hps with Shield->Flash x3->repeat for crystal soakers. Should be noted that Atonement does get increased heals when it hits the tank but since you can't be sure its going to hit the tank its not very reliable;
Staghelm: We did the "normal" method of pushing Scorp as high as possible and 7 leaps on every cat. Just like on Beth p2, AA is very good here and Barrier is just OP, especially with glyph. Also its not a good idea to keep a disc outside of the scythe as the PWS doesn't benefit from Concentration, so better leave it to Druid or Shaman (2 healing it). During cat Atonement and Penance pretty much keep the tank up and help DPS.
Ragnaros: We are still progressing on him (reaching p4), but its a holy fight for sure so no help from me =)

Hope it made sense as its not my native language.