About %'s, it's not rly something like "start aoe at 45%, it will be ok for sure". I usually started it around 45 and continued it for whole T2, and it was ok. But can't guarantee it will be in your case . Be sure to make P1 as short as possible if you want to get rid of adds. With this strategy I was able to get like 130k vengeance during P2 and just like 50-70k during P3. That makes difference a lot.
I know it depends on gear, but what % do people generally start AoEing the ghouls down (25H)? I either kill them off too quickly and die during the phase change, or don't even come close to killing them, and subsequently die in the Frostmourne phase. I mean, I REALLY wish they'd fix that bug, it's making this ridiculously frustrating (considering if you've gotten that far, you've probably got both the gear and skill the finish it and most certainly are capable of running through the FM room phase without dying), but until they fix that/if they ever fix that, what % should I be looking to start AoEing?
"The Bug".. well. I prefer to see fight as it is, rather than seeing something they made with Kalecgos in SWP. Yuck. They should remove ghouls going further into that way of "making things available for everyone". Imo first 2 phases require same skill as normal, if any. P3 itself.. it was always ment to be worst, wasn't it? What skill require moving away from giant black circle that will explode after 3secs. What skill is needed to see that valkyr you're attacking is below 55%? Third phase - frostmorune, ghosts, bombs, defile, spirits (pala soakers ftw!) oh and 30M on lich king in the meanwhile
First time I did it with "~10mins P1 strategy" was around 510ilvl. Keep in mind that you won't need expertise with 70% overal damage of avenger shield. Just softcaps, haste makes waste. It's around 480-500k dps needed to kill it before frostmourne. Makes easier when shamblers start to berserk (6mins after they are summoned, they get enrage for good). Currently im around 520ish in protspec and tbh.. I'm using fast shitty weapon (dalaran sword, 1.8speed lol, srsly) for fast SoI ticks there, and force part of adds to attack my back during P2-T2, for more vengeance (few steps back, few steps forward quickly). Nothing rly happens. 2 nobrain macros that are helpful:
And just spam
/cast Avenger's Shield
About killing raging spirits.. I would suggest to keep them alive, or kill lets say max 1-2 total (probably just to "feel safe", it will have no big impact on the game anyway). For sure you shouldn't do it in P3, it's guaranteed berserk.