[2.5] Inquisitor Skin of the Loyal Scorching Ray. The Lazorphile.

With a heretic, You definitely should run Disciplne + temp + flam + Enlighten. That is the only possible way to run tri curse aura. BUT that means you have very little mana left, and will need to invest in some mana nodes and mana gear to sustain your lazor.

I am looking at it in detail now I don't know if heretic's veil and 2 curse auras is worth the tradeoffs. Maybe I will just stick to curse on hit/orb of storms Temp Chains.

Can you try and take of your SotL to see how much ES it gives you? I would like to know if this is still viable with a +1 tabula. Those are A LOT cheaper

I have 11k ES with Discipline on, and Sotl takes away about 2k when I take it off. You definitely can use a +1 Tabula, if you want to live in the danger zone.

Level 75 currently running with a high budget.

I think this build has great clear speed especially on open layout maps and breaches. Not so much on crowded ones.
I am at 24k tooltip right now in my hideout. I think I can get to 30k with more levels and eventually upgrading to two opal rings plus fingerless silk gloves rares.
My gear so far:

That is some beast mode gear right there.

If you had infinite RNG, which Keystone upgraded Skin of the Lords is the best?

Unwavering Stance comes to mind. By far it is the hardest to travel to by most CI builds. This free up the Amulet slot for a nice amulet, maybe a cheaper +1 curse amulet than Eye of Chayula.