The way I use it is to DoT as much as possible and keep killing mobs until my mana is at around 5%. With Canni + HoT pots + Epic click + Ancestral Aid, using my mana pool can take a while, but gradually the mana goes down. When I get to 5%mana I use GRB + SC and carry on (continuing to use HoT pots if needed). By the time SC has expired my mana is 100% again and the cycle starts all over. If I am religiously hitting cannis as they pop, and only using mana-free HoTs, the decline to 5%mana is around the same time for SC to pop again. If SC isn't up and my mana is gone .. I take a few minutes for a coffee break
It's a bit of a balancing act and occasionally I might have to use Spiritual Serenity when HPs go low if I accidently get in melee range of a VP'd mob.
