I do understand that heal meters shouldn't be relied upon. I just have limited experience as holy, so I wanted to make sure I was in the correct threshold.

As for HN, i only had about 21% overheal, while PoMs were at 26%.

Anyway, here is the WoL if it would help.

World of Logs - Real Time Raid Analysis

How do you control the over-heal on your PoMs to be less than 10%? The largest source of over-heals as holy for me has been PoM and I can't figure out how to prevent that spell from over-healing, especially since it is such a monster on this fight.

You can't control overhealing on PoM except to make sure you place it first on somebody who is likely to be hit hard, e.g. a tank or someone standing next to a person with Touch of Light/Darkness. After that it will bounce around beyond your control.

The only other thing you and your other healers can do is to be conscious of where PoM is. PoM is a smart heal in that it will always bounce to the person with the lowest health within range. That's also the person with the largest visible health deficit and therefore likely the same person every other raid healer is targeting with their next heal. In the same way that people can "snipe" a HoT's heals they can snipe PoM:

PoM lands on a low health target -> "helpful" healer hits them with a heal topping them off -> the periodic damage aura ticks dealing a small amount of damage thus triggering PoM's heal which is now mostly overhealing.

The only way to prevent that is to see that the target has PoM and direct your heals elsewhere knowing that they are going to receive a heal from PoM on the next periodic damage tick. Generally speaking, though, nobody tracks PoM except Priests and most Priests only track their own. That said, you yourself can make a conscious effort not to snipe your own PoMs.

Removed, looks like the message was answered before.

Yes, Bubble-Sac + Fire Resist Aura Mastery are both key to healing through light vortex if everyone is dark charged. Having every druid (including non-healers) use tranquility helps as well, as does priests using divine hymn.

You do know part of the door strat also involves blowing a ton of cooldowns. Everyone in the raid who has a survival cooldown should be blowing it, and your Paladin's should be specced into Divine Sacrifice and Aura Mastery.

My guild doesn't attempt to heal through it; however I believe the first guild to post a video with the door strat also had their DK's doing Anti-Magic Zone.

Besides that though, it's expected your mages are using Iceblock, your druids are using Bark Skin (and/or Survival Instinct), your warriors are popping Shield Wall, rogues are popping Cloak of Shadows, etc etc.

That alone mitigates a lot of the damage. Mages, Paladins and Rogues should take 0 damage. Also, from what I saw, during the vortex, other classes who can heal, will heal: ie, Enhancement Shaman and Elemental Shamans were tossing Chain Heals during the vortex.

(P.S. if your Paladin's don't spend the 1 point in Aura Mastery, drop them and get some semi-competent Paladins).

Aura Mastery is also incredibly useful for Jaraxxus and even Faction Champs.

There's a great deal of utility from that talent point, so I'd encourage your paladins to pick it up.

And abusing Raid Wall until they "fix" (nerf) it in the patch can't be a bad thing imo. Using raid walls and aura masteries can help quite a bit in certain parts of certain fights.

You should be able to get to phase 3 with only one submerge. Then you have 5 frost patches to use during the kiting, which is more than enough. At least if you have a paladin healer with you, the dps requirements should be pretty trivial. It's not impossible at all to do phase 3 as holy, but I found it much easier as disc. Just keep a downranked renew on those who need it, and shield the ones with Penetrating Cold, then heal them.

If you need two kiting phases, then you're probably going to be needing two paladins for HoP. It is possible to use Pain Suppression and spamheal though, if you're lacking a second paladin. But again, a paladin on both tanks and a disc priest on raid is pretty much optimal for this fight. Relying on B&S for kiting a few more seconds sounds very risky.

While we've never had 2 paladins for this, we successfully use the door strategy with 1 Paladin, 2 Disc, 1 Shaman, 2 Trees, which is similar to your makeup. You don't mention PoH as something you use, but it's the perfect tool for Light Vortices. As mentioned above, it's critical that everyone uses damage reduction cooldowns for vortices - even small effects like Shamanistic Rage make a lot of difference.

We use 2 tanks, and have one group of Light DPS - all ranged backed against the grate to avoid orb damage - to help with Twin Pacts. If your group is all Dark except for soakers, it's possible that switching a few people to Light could reduce the burst healing required by shifting some of the damage to the other vortex.

This fight is doable if only a few people are forced to take the off-color vortex instead of having nearly the entire raid soak it. We have done it where all the dps switch if needed on vortex.

The only really notable pushback that springs to mind is the twins' vortexes. If your strat doesn't require you to heal through vortex without changing color, I think TotC is pushback-free.