The only items that I think is BiS is Gloves( for that juicy 10% of flat poison) and hat for -cd to Blight Fiend. I still dont know about amulet though. Ive tested soveren rubi( only on dummy) and its was not so impressive for some reason, i only got few seconds on kill time.
Also i tried that epic amulet for 2 poison bugs. And oh boi do they suck! The amounts of damage that they deal is just painful to watch. They definitely need some work. Like maybe if they were just suicide bombers that leave after death poison pools with dmg similar to blight fiend death ability, then maybe.
As for conduit itself I use it cause of its amazing resists and +1 to necro. Mod is just I dont know. It says that Blight Fiends gain additional Taunt, but its just dont work sometimes. Even with Ishtak they fail to hold aggro. So I dont know really.
Also I tried Bysm domination relic. It`s good kill times improved a bit, but I had a feeling that my char became a little more fragile for some reason.