Originally Posted by
snaxattax
yeah, healing effectively as disc involves a lot of planning. be sure to use a boss mods addon like bigwigs or deadly boss mods. when you have <10 seconds for some big burst damage (unseen strike), use archangel, innerfocus and spirit shell and start POHing each group. then the arrow pops up and you all stack and get hit. as soon as you get hit, pop cascade, as it will keep bouncing as your raid regains composure.
i've personally found that the timers can be kinda goofy for unseen strikes, and that you can't always get every single unseen strike with spirit shell. in this case, when you stack make the other healer use something like spirit link and you can use PWBarrier. it's also a good time to use PWShield on multiple targets so that you get a multi-rapture proc when they get hit. you can still do the cascade trick to help heal people back up after the hit.
you should be able to alternate between spirit shell and external cooldowns (barrier/slink/rallyingcry/demobanner) to make it through the fight. don't forget to do another spirit shell when the boss hits ~11 or 12% so that people are topped up for the 2nd tornado run (or slipstream if you use that strategy).