shouldnt he be at his 2-3 annihilate around 10%?
easiest way for gear is:
buy all haste/versatility up as cheap as possible (ilvl as low as possible, cheaper repair)
with a jewelcrafter get the neck (karazhan midnight neck is better) and rings slotted
maybe the karazhan quest hands if you didnt do it before
first boss emerald dream trinket
legion artifact for double enchants (farm some first boss dungeon for artifacts - reset d.)
hellfire citadel bird boss trinket (maybe lfr fast farming-only once a week ;(; balance spec ? )
prolonged power for before entering mage tower
i do drums at start (for one elemental) and fury pot for kruul
warscroll if you can
hidden satyr neck enchant!
some food
both oils
p1: keep the 2 boomkin dots up + thrash 3 stacks all the time
start with a good boomkin rotation until first horrors and then bear berserk near boss
to get the 3 stacks of thrash running while killing the horrors with it. 2 stacks of that ground aoe max. so you dont die in owl form after. use defensives. 
p2: circle like running backwards outside of the middle. middle for horrors pick up…
get a weakaura that announces with a sound the interrupts and annihalte. with so much going on at once, those sounds are worth making the adjustments!
got some decent tries with that. still need luck with positioning. and the horror nerf in p2 is quite bad. if i must do an orb while horrors are at the portals, its a wipe most likely for me.
but one thing is certain. they never played it themselves lol