The only stat you are going for is spellpower. No haste(!), no spirit(!!!). About not gemming spirit I’m super cereal you guys :^/
Red Socket=> Runed Cardinal Ruby
Blue Socket=> Runed Cardinal Ruby
Yellow Socket=> Runed Cardinal Ruby
What you could is play a bit with crit but that’s only when your bubbles are at least of 10k-11k damage absorb. However, I’d rather you pick orange crit gems instead of going for a full, yellow one.
One more thing,
Which meta do I pick?
Insightful Earthsiege Diamond
But, but, it needs a blue gem for activation and you said to gem full spellpower?
Purified Dreadstone / Seer’s Eye of Zul / Nightmare Tear