Some kitchen ingredients better than others for clumping??

Thanks for suggestion of Stampede, Act 6 Crisis and Death Mark. While I've now finished the training for my giant, I'll try the latter two for my human and elf.

I'm not following your suggestion re Crisis Escape and Raincast. If I lose agro I'm getting too many mobs wandering outside the damage radius of my hydra, so I'm not progressing the hydra training requirements.

The strategy involves using Raincast, dropping aggro (with Crisis) whenever you might get it (rank 1 Raincast doesn't entirely prevent aggro), and then using Hydra. If enemies walk outside of the circle I kill them with things like on-summon pet damage (for example, bone dragons deal damage to a flight-line when they get summoned that can hit even enemies far from you) and dance of death. Those two examples might kill enemies that are within hydra range, so you might need to micro manage a little. All of these will stun the enemies when they get hit and prevent movement for a second (you can include Shock for stuns that will likely not kill the dungeon monsters).