I currently run a SoS build on my disc priest, but I've been reading (mainly on here, but also on talesofpriest) that Atonement is great - and almost required - for some, if not most, heroic fights. My guild is currently 7/8 in 25m DS and we're pushing Madness hard and fast. Therefore, I'm considering trying out Atonement for a week or two in normals while we're still there, but I know next to nothing about healing as Atonement/AA.
My usual healing setup for our raids (I'm the healing officer) is 2 resto shams, 3 priests (1 disc, 1 disc/holy (me), 1 holy), and 1 holy paladin. Therefore, I sometimes have to tank heal with the hpally as our primary disc priest is sometimes.. subpar. Is Atonement/AA possibly viable for both raid- and tank-healing?
Otherwise, lets assume I would be doing more raid-healing for discussion's sake. In this case, what do I need to know? What are my stat priorities, important glyphs, and useful addons I should have? Basically, if there is a guide somewhere (couldn't find one here) that is widely used and regarded well, where is it? Otherwise, any and all help is VERY much appreciated.
Thanks for your time!