For those times where you know you'll need a big heal, I like to preemptively use Internal Release and have either Berserk or Bloodbath ready to pop with Inner Beast (you can normally time usage so that you always have a 2x CD buffed IB); outside of that, when there's no spike damage mechanic to watch for, I try to have one CD (IR/Berserk/Bloodbath) ready for IB use so it's always buffed when the heal is needed.