Min/Max'ing Raid Comps for OS-10 3D

After polishing off an Undying run in Naxx-10 last night, I've been pumped up about finishing Glory of the Raider. The crowning glory in that achievement-pack is The Twilight Zone, which is accomplished by defeating Sartharion in Obsidian Sanctum with Shadron, Tenebron, and Vesperon still alive at the start. This is considered the hardest thing to do in Warcraft currently.

I've set my sights high.

I'm going to roll with a 3-tank, 2-healer set-up. With the help of MMO-Champion's RaidComp feature, I've been playing with raid comps and trying to min/max it so that I can squeeze every last drop out.

According to StratFu, it's best to focus on magic damage or physical damage for the DPS. Under that assumption, I've created a magic-centric and physical-centric comp to discuss.

Magic-centric comp
In this comp I'd need to spec prot and tank drake(s) and whelps. The frost DK would tank Sartharion, and the prot warrior would handle the other drake. I chose the DK to tank Sarth because of his ability to use a cooldown just about every breath. The holy paladin would handle tank healing, and between Beacon of Light, Earth Shield, and Chain Heals, the healing is hopefully covered. Replenishment from the shadow priest, Ferocious Inspiration from the hunter, and the rest of the yokels buff each other with magical fun. The DK could be unholy as well, I'm not sure it makes a difference. Additionally, a feral druid could be used to main tank Sartharion.

Physical-centric comp
This comp can tear a single target to shreds, but I'm afraid for its ability to deal with the whelps. The only true AoE in this group comes from the 2 hunters - the rogue has Blade Flurry, the tanks have AoE stuff, and the ret paladin (me!) has Divine Storm and Consecration, but other than that, they're hosed. However, the group does have everything else it needs - both armro debuffs, 2 blessings, an AoE tank (prot paladin), a tank healer (disc priest), a raid healer (resto shaman), Replenishment (ret paladin), etc. Either the prot warrior or feral druid would tank Sarth, and the prot paladin would be on whelp duty.

How would you fine-tune these comps to the Sarth-10 3D fight?

EDIT: And in case I feel like going with 2-tank, 3-healer comps:
Magic-centric 2 tanks
Physical-centric 2 tanks