Quote Originally Posted by Kabooa View Post
If you have 80,000 HP as a tank, and are taking an 80,000 buster.

Heart of Corundrum: .85 * .85 = 57,800 damage taken + 900 potency healing. At ~1500 HP per 100 (lowballing), restore 13,500 health.
Final HP: 35,700
+Brutal Shell: 38,700

Bloodwhetting: .9 * .9 = 64,800 - ~6000 (400 shield) = 58,800 damage taken + 1200 potency healing. At ~1500 HP per 100 (lowballing), restore 18,000 HP.
Final HP: 39,200

Please note that as damage intake lowers, the better healing potency is, likewise as damage intake increases, mitigation is better.

This also assumes both tanks are already full HP. If they instead are down one auto attack worth of damage, Bloodwhetting wins out and it isn't even close.
I just did the math myself.

If you throw in your 30% (which you're supposed to do) to both jobs, you'd have to crit at least one of the heals (which you can force with PR or IC, mind) to significantly beat out what GNB can do in the span of 4 GCDs, even if you're assuming both tanks are 10k down from an auto. And if you crit that HoC heal, you'd have to crit two BW heals to significantly beat it.

(mitigating another 10k auto after the TB with or without the 4s 10 and 15% buff active shifts it under 400ish HP in favor of GNB as well)

With all that in mind, BW is much more likely to overheal over the span of 4 GCDs depending on what your healer does, which biases it vastly in favor of GNB, which is I say that HoC is better. Overheal is much less likely on GNB unless the buster doesn't bring you under half health.