Important: Ideally use
Horror's Flight with Culling Strike rune. If you cannot do this...
Use
Deathblow gloves instead. This allows you to cull everything (including instantly killing all normal mobs) but rares/uniques will be harder to cull (rares will cull at ~33% life instead of ~53%).
Heart of the Well Jewel: The main mod you need is "%increased culling strike threshold" as high as possible. Everything else is just extra.
Note: Across all gear/passives you want a minimum of 186% generic culling strike threshold (not including what you get from
Horror's Flight) to instantly kill normal mobs.
Since damage is not needed we're able to focus on strong defenses and stack anywhere from 8-10k+ energy shield with about a ~2second delay before it starts recharging. We're immune to chaos damage thanks to
Chaos Inoculation, so really just make sure you cap out your elemental resists. We get a huge amount of defenses from our jewels, and thankfully they're very easy to make/trade for. You really only need maximum energy shield on them, and then corrupt to try and get some resistances added on top!
Note: Your wand doesn't really matter. Grab any 2 socket wand with cast speed and that's all you need.