I save an aetherflow charge for Bane when I know a difficult Conflagration is coming up. Pre-cast Miasma and Bio II on Twintania, Bio when the blue icon appears. Bane as soon as the conflag pops.

The beauty of this is that you could cast the spells fairly early before the conflag icon appears, so you could potentially cast in between DS with plenty of buffer time before the next one lands.