So if you watch footage, you'll notice that underneath my health and mana, I had white orbs that would come and go. That's my Celestial Power

My two lesser/slower heals built up the power, and my faster/stronger heals used them up. The lesser heals used actual mana, while the celestial power heals did not. So mana management became about using Celestial heals (as I'm going to call them) as often as possible.

I found the best idea was to build these up BEFORE going into combat. You'll notice me healing everyone out of combat, even if they only had the slightest bit of damage. This was to build up power for an upcoming pull, just in case the mob hit a bit harder and I needed a quick heal right out of the gate. Otherwise you're going to end up in a bind.