Forbidden Rite Int stacking

I've been working on an idea regarding Forbidden Rite. I believe Int stacking to be a good way to build both defenses and offences at the same time.

Offense:

• Base damage through high ES (~20k)
• Damage scaling through Tranquility/Transfiguration of Soul, as well as Whispering Ice (Spell damage per Int)

Defense

• Very high ES (20k)
• CI (no ES damage)
• High leech rate (4.2k)

POB based on a Whispering Ice Int stacker I found on POB. Rather Min-maxed I assume. Simulating Forbidden Rites damage through a Dark Pact with high skeleton life, damage ends up at ~1M DPS (with Wither stacks). If the projectiles shotgun, it'll be great. If not, damage seems lack-luster?

POB: https://pastebin.com/F0GRjbmt