Nice stuff. The trickiest part for me on MTing Garuda EX is managing Wicked Wheel. I've had instances where it comes out before she teleports, and instances where she uses WW and doesn't teleport at all, which has thrown my timing off. I believe it's tied to DPS on the OT's sister, but I'm not 100% sure.

Also, is there anyway to "force" the Spiny plume to aggro onto a player, or at least prevent it from spawning latched to the MT? I find it much easier in the tornado phase if the Spiny has spawned on anyone EXCEPT the MT, as this allows that person to build 2 stacks up, then lets the MT use Provoke on the Spiny, and the OT to Provoke on the sister that the MT currently has. So in a nutshell it would go for example:

WHM: Spiny Plume
WAR MT: Garuda+Suparna
PLD OT: Chirada
Chirada dies and Spiny puts 2 stacks on WHM

WHM: None
WAR MT: Garuda+Spiny (Provoked from WHM)
PLD OT:Suparna (Provoked from WAR)

But during my last run, it kept spawning on the MT, which prevented this strategy (as OT, my choice was either Plume or Suparna. The choice was quite clearly obvious to avoid the wipe, but made it harder for the MT and healers)