[Shadow] Psychic horror and aoe tricks in PVE

[Regia]

Insanity - Talent
Requires Priest (Shadow)
Requires level 45
Consuming Shadow Orbs transforms your Mind Flay into Insanity, and your Mind Sear into Searing Insanity, for 2 sec per Shadow Orb consumed. These spells deals 100% additional damage.

^ Because I know there are shadow priests who haven't yet realized that we have a second orb-consuming spell, not just Devouring Plague...and it can operate with just 1 orb :P

Psychic horror can be a direct AoE DPS boost if used correctly in PvE. This isn't the sole point of the thread (had a question about its use with RoW) but I'll recap it just to clarify for anyone who hasn't been using the trick, since I haven't actually seen it discussed here.

Firstly, a set of rules I use for COP AoE...
If you are trying to spam searing insanity, you want to keep the channel going, but also keep an eye on any opportunity to return yourself to 3 orbs. If you can snatch such an opportunity, clip your cast to do so, preferably either timed around the CD of mind blast, OR be quick in such a way that you won't lose your current Insanity buff and can continue using it. If such an opportunity (to get back to 3 orbs) isn't going to come up anytime soon, hold onto your channel until the very end, even if mind blast is off CD.
Same goes for whether you should interrupt yourself (and drop your Insanity buff) for cascade. Do you NEED to do that right now? I.e. do you need to do it so that you'll have it up again faster and be able to use it more than once? Do you need to do it before these adds die and you miss out on cascade bounces? Or can you hold onto it and time it with your orb-builders so that it doesn't throw off your searing insanity rhythm?
Searing insanity aoe seems like just simple spam, but it's actually a bit of an ongoing prediction/decision-making process due to searing insanity basically snapshotting your buff.

As for where Psychic Horror falls in there, it can "save" you when your rhythm gets thrown off.
Situation should be as follows:
You have only 1 orb.
There's a big pack up that needs to be aoe'd.
You aren't going to get to 3 orbs anytime soon, because mind blast is freshly on-CD and nothing is approaching execute range.

Simply put, throw a psychic horror at anything (even if it's immune!) and you will trigger the Insanity buff on yourself for about 1 second. If you are quick to start a searing insanity channel on something, you can hold onto it until the end. Often, this can buy you time to get back on track, i.e. cascade coming off cooldown, mobs getting burned down into execute phase so that you can return to 3 orbs and fire off a "legit" searing insanity cast :P

My question, since I don't see this being used often, is whether this trick is ever worth using as an opener with Repudiation of War on a singletarget fight (assuming you don't start with any orbs). After mind blast, you have to open with mind flay to get the trinket debuff stacks up. Is it worth sacrificing an orb off the bat to empower this initial, mandatory mind flay with Insanity? You are trading 1 orb for double damage on that mind flay...so how would one figure out how much damage 1 orb is "worth" exactly with COP singletarget?

[Sxq]

I remember a little bit of discussion about this a few months ago; I'm like 99% sure that there's no way to game it in such a way that it's ever a dps gain in single target, even on the opener. Losing an orb is bad, and you also need to remember that the duration of the insanity buff scales with number of orbs spent. You only get 1 GCD of insanity if you spend one orb on horror. This means that you can, at most, do MB->horror->4tick insanity instead of gaming the insanity to get 6 ticks with a mind blast in the middle. Not a dps gain.

It's sort of nice to do occasionally if you need to do searing insanity and have no orbs, although my experience is that in most practical situations this doesn't really occur unless you make an error since it should be possible to plan ahead and have orbs ready.