Atm , its an hps increase compared to simple healing spells, with the condition that you have incoming dmg to consume it: if the dmg already happened, SS wont do anything obviously. Prayer of healing is the spell that will give you the most hps increase with SS atm, but it doesnt mean its not a good tank cd too: its absorb is bigger than the normal gheal.
For some fights, you will want to use it before massive aoe on the raid: Force and Verve, Unseen Strike, Rain of Blades, Crush, zone explosion on Empress, Arcane shizzle on Feng etc. Look at boss timers and try to stack it before the dmg happens, so you will want to start stacking shields about 15 seconds before (less on 10 man due to SS capping prolly).
Even if there's no deadly ability to make the most of its gib-preventing abilities, its still an hps increase any time there is aoe dmg inc.
To maximize potential, you can use it with archangel and Inner focus. Be aware that in 10 mans (or when used for tank healing), it caps pretty quickly (60% of your hp, also less likely to be a problem when tank healing since the shields should be eaten before you cap them).
In order to use SS in the most effective way is to learn the fight well. You'll see that some fights are predictable and you can use SS before incoming damage as described by Saphiramoon. You'll also notice that some fights are not due to RNG boss ability or not synced CD with boss major hit. I don't use SS on CD but save it for some nasty hits like "oh shit" situations if no other CDs can't (not available) be used. SS on low health player will buy you and other healers time to heal up under absorbs.
In order to use SS in the most effective way is to learn the fight well. You'll see that some fights are predictable and you can use SS before incoming damage as described by Saphiramoon.
This is it! Have accurate timers like DBM or BigWigs. (Or both.. DBM Timers are pretty bad for Rain of Blades)
List of application areas:
- Vizier (Hof 1): Force an Verve
- Bladelord Ta'yak (Hof 2): Unseen Strike, Transition to P2
- Garalon (Hof 3): Before every 2nd Crush
- Windlord (Hof 4): Rain of Blades (only with good timers)
- Empress (Hof 6): Before every Explosion of the yellow Zones (Can't think of the name, you have to time, when the are going to explode!)
- Sha (Terrace 4): When on a plattform, then you are safe to collect bubbles
- WoE (Mogu 6): Before titan gas
- Feng (Mogu 2): Arcanephase, Firephase
If you do 10 mans, you'll need about 8-12 secs to have a capped shield on both groups.
What I meant was, what spells and abilities should I be using before I cast spirit shell, and is prayer of healing the best spell to use once I pop spirit shell?
make a macro that pops archangel (especially on 10 man you should be doing lots of atonement as your filler, but otherwise make sure you have a 5stack of evangelism up when you're going to be SSing), innerfocus, power infusion and spirit shell. find your POH hotkey and go hogwild.
for example, like 6-7 seconds before arcane velocity (feng's spinning arcane damage thing) pop your macro, and start POHing group 1 then group 2 then group 1... even while it's doing the aoe dmg keep POHing back and forth between groups. you'll notice that your raid's HP will barely budge at all, except maybe a little at the end.
same can be done with draw flame and/or epicenter (assuming you can't manage to stun/barrier each epi).
SS works best when the raid damage comes in discrete bursts. if it's more protracted it can be harder to get the shell 'stacked up'. even then, however, it's still good to use SS instead of pure healing as disc mastery makes SS a throughput increase.
SS stacks extremely well with PWBarrier and demo banner, as it makes the shell last longer (giving your other healers more time to top everyone off). this is very useful on extreme raid damage phases like heroic vizier's force and verve.