This build is using 7 needle horror spectres (a mix of perfect and regular) it doesn't really matter which version to use. The main damaging spell they use is physical firestorm which opens up couple of ways to scale it. This build focuses on converting all to chaos damage and scaling poison, the chaos hit(crit) variant is also good. Im also using 1 Perfect Warlord in a separate Raise Spectre gem to generate endurance charges and proc feeding frenzy.

My PoB: https://pobb.in/jLb0ncQ1ZRiS

https://poedb.tw/us/Perfect_Needle_Horror#PerfectNeedleHorrorBarrageDemonHigh

Get Needle Horror corpses from Ritual or just simply buy from trade site.