I use Shroud of Saints when sisters first pop (pre-tornado phase) and then every time it is up after that.

In tornado phase, when the sisters are summoned the whole party should already be at full health and stoneskin on both tanks. So no regens should be active and no healing should be necessary. Not until the tanks have pulled their mobs to their assigned spots and have hate well established should you need to cast your first cure of this phase. Just refresh stoneskin once on the MT while you wait and then start in with regens and the healing once frictions start.

Quote Originally Posted by Jeykama View Post
For tanks, it is possible to do a Fast/Skull at the very end of Mistral Shriek, Savage/Heavy when Garuda respawns, and have Halone/BB up for the sister to have gg threat for that phase, but as I said the timing is very strict and 1-2 seconds off will lose the combo.
^It is good for your tanks to do this if they don't already.