What makes WHM special? Nothing anymore.

[GideonHighmourn]

CU's total healing potency can be cheesed if needed, leaving and reentering the field refreshes the HoT so CU can potentially have 1500 potency but it isn't easy to do.

If you have time to stand still and channel for the entire 18s, chances are you don't need the healing anyways.

Also, Asylum is less for DPS (if you're placing it like that) and more about the tank, which should know to stay inside the bubble if possible.