Jin'rokh the Breaker:
Better to use Touch of Karma to do some dmg and the next storm do the Diffuse Magic.
only use Zen Meditation if the healers have problem topping every one up.
Horridon:
If you get high stacks of debuffs and the healers can't prio you then you can use Diffuse Magic to dispell it and Touch of Karma to do some more dmg. On the second and third gate you can help the healers with Detox.