They capped negative resistance at 200% but resistance penetration is a different calculation AFAIK.

What if we stack Omniscience through the nose and used Mjolnir to deliver Arc? To that end, I made a tree which is as long as possible so that the Split Personality jewels at the very end deliver a real lot of Omniscience. Since Omniscience takes care of elemental resistances we can use all the suffixes for attributes and we certainly do that. Where we can, we sneak in a little increased attributes, too. It also takes care of the Mjolnir attribute requirements.

Our main skill is Cyclone, on critical strike (38% crit chance) we cast Wave Of Conviction which, together with Master Of Discord lowers lightning res by 40%.

I threw in the Gull just for fun. It's great fun especially when the atlas has a passive node to strengthen our shrines.

My rule in creating this was: no item can cost more than 1ex -- closer to 0.5ex, really. I copied the items from trade, these are real, not made up items. The Split Personality jewels would be better if they were dual attributes but those start at 1ex so I didn't do that.

https://pobb.in/PyUZtzc2Ubdf