Not on heroic, at high RP, sub 30%, marks are taking ~12k damage every .8 seconds. And the problem is, nobody needs or cares about cooldowns at low RP when you can actually spare the GCD.

As I said before, you can cast an instant and keep people up with FoL, but only at low RP. If you use an instant at 90RP, you will then have at least 2.2 (for my haste, 2.7 if I judge) seconds in which there is no healing on the target. At 11k damage every .8 seconds, that's maybe 33k damage on the target (in 2.4 seconds, not unheard of considering you cannot queue spells during the GCD). Hell, if you are unlucky and that person gets a blood boil that ticks at the wrong time, you can end up with 28k damage in .8 seconds. So I would say that from personal experience, you cannot spare a GCD at high runic power, which is when divine guardian would be most useful. Yeah, maybe you can do it at low RP and risk a DP without any other CD, but that's still 2 GCDs in which you're not healing which could result in people dying.

Judging or refreshing BoL is doable, do it just as he casts a mark, you have 2-3 seconds of no damage on marks/tanks then, and since they last over 1 minute, it's easy to keep them up by refreshing at the right time.

What do you mean if it were true? It is true.

0.0 -- Finish HL, target is healed to full. Cast DSac.
1.0 -- GCD finishes. Cast Holy Shock. Target has gone 1 second without heals.
2.0 -- GCD from HS finishes. Start casting HL.
3.3 -- Finish casting HL. Target has gone 2.3 seconds without heals.

All holy shock does is delay the 2.3 second window. In situations where your target has multiple healers, or where you're dealing with a short burst then period of respite, this delay can be negligible. In situations where your target is guaranteed to take X damage every 0.8 seconds, it's utterly irrelevant.

As gcbirzan pointed out, DSac is a catch 22. When you can use it, it's not needed, and when it might actually help is when you can't spare the GCD. I can't speak to your experience. Perhaps you're using it at low BP values, perhaps your other healers are covering for you, perhaps you've gotten lucky, perhaps a million other things, but at the end of the day using DSac isn't ideal. It might be viable, but it's definitely not ideal.

You got me on the Holy Shock thing, not exactly sure what I was thinking there, but either way I'm still sticking to my argument that Divine Sac is worth using.

I'm not saying to use it at High Blood Power or Low Blood Power, I'm simply saying to use it during, or as he uses Frenzy. Aura Mastery doesn't exactly hurt either.

If you don't use Holy Shock after the Divine Sacrifice, I'm only seeing Divine Sacrifice as helpful, as it really doesn't put your Mark target in any sort of danger, assuming they were topped off, even if they are taking "11k damage every 0.8 seconds", which I can't personally attest to, but I'll use that number anyway.

0.0 -- Holy Light finished. Divine Sacrifice.
0.8 -- 8.8k damage (20% reduction).
1.0 -- Global up. Cast Holy Light.
1.6 -- 8.8k damage (20% reduction).
2.3 -- Holy Light finished.
2.4 -- 8.8k damage (20% reduction).

Your target is taking 17.6k damage without getting heals, which is a survivable amount. Also, keep in mind that it's effecting everyone else in the raid, not just our targets. We're lucky because keeping a mark up is extremely easy for us, but for other classes, it can prove to be somewhat difficult when paired with a Boiling Blood with no BoP available.

Assuming 5 Marks are out, a Divine Sacrifice would prevent 77k damage in a 6 second period, from the Marks alone. This doesn't include the large amount of damage the tanks are taking, or the amount of damage that Boiling Blood is doing to the raid.

(11000 * 7 * 5) - (8800 * 7 * 5)

It's just important that you use it when it's safe to use it, and not when your Mark is at 50% HP. Feel free to correct me if I'm missing something.

Couple of things there. First of all, there's a delay between activating the buff and the raid getting it:

[23:47:50.335] Ungulant gains Divine Sacrifice from Ungulant
[23:47:50.339] Ungulant casts Divine Sacrifice
[23:47:50.650] Vesi gains Divine Sacrifice from Ungulant
[23:47:50.650] Specializer gains Divine Guardian from Ungulant

Also, you're assuming there are no hits at T0, where in reality the hit might happen at T0+.1s. You cannot queue spells after the GCD so you need to add .1s+lag to that, you also aren't accounting for the erratic BoL heal lag which might delay your heal long enough for that person to die. And to top it all off, the range on the DS/DG is 30 yards, which isn't nearly enough to reach the whole raid.

I can confirm this. We had a druid healer dying because he just kept Terenas alive, while healing him to full health made him kill the spirit very fast. I think the reason for myself to be slow on this was that I didn't dispell the thing on Terenas. So the advice is to heal him to full, stun the mob and dispell his debuff

5 Healers? Is the idea there that your boosted raid dps means fewer marks anyway? I think the spiky tank damage on swaps (while predictable) might be down to tanks slacking on taunts and eating a marked swing or two.

Also- aye, I'm primarily conserving mana big time at the till the first mark, but after that I end up having to really up my throughput for the rest of the encounter since the amount of help I get on the mark will swiftly thin out. It's mostly just beacon and the odd HoT or incidental chain heal etc.

One thing to note regarding HM Saurfang is that you will most likely have heroism/bloodlust for the beginning of frenzy (we always pop it at 30%) making the time between you popping DiSac and landing a HL again that much shorter.

So what I've picked up on this forum is that I am supposed to cast as many Holy Lights as possible and almost go out of mana right at the end of the fight. And that Intel allows me to do that better than any other stat.

Still I am wondering about fights where there are breaks in healing like Marrowgar or the Gunship Battle. Would it be better to have a bit more Spell power instead of Intel? So if the model changes from steady healing to spikey healing, does Spell power move ahead of Intel in value?

I guess we will just have to disagree on this point, as I don't see .3 seconds off my holy light as a trivial amount, especially on that encounter.