Best Ethereal For Corpse lancer Necro?

Currently going over some theory for a Corpse Lance T16 /low GR speed farming build. Where Borrowed Time Curse is also spammed for CDR.

The Cinquedea seems to be giving the highest sheet deeps plus it has the %elemental damage increase and the plus 100% damage to necro skills is also Additive ?

I just wonder if the cursed enemies Fear of the black hand key wand triggers Krysbin, would that not give more actual DPS if this is Multiplicative ?