PoE Despair, Spell builds

Hello, i've been thinking about build based on Caustic Cloud spread by dying zombies but I'm not experienced with summoner builds. Its base damage is really huge so it's really easy to achieve huge dps, it lasts 4 sec btw Most of my problems are mechanics. My current plan is to detonate zombies with Coruscating Elixir(Umbilicus Immortalis to apply flasks, Maligaro Lens for 1.2k life heal per zombie) or eventually summoning over max(yes it works) but I don't think it's enough. Zombies are meant to die so they are rather low defence, I can't get any special spectres because Flask would kill

Edited updated build I have made this build, please tell me what you think. The goal was decent regen, leech, high dps, chaos convert so we don't have to worry about pen. The gear in the build is not great, but decent and easy enough to currently get for cheap.

I've fallen in love with ED the past few leagues and decided to theory craft this build while waiting for incursion to start. My inspiration for it was the instant cast of both contagion/ED as without cast speed this interaction feels pretty bad. Here's the pastebin for the build, imported direction from in-game - Skill gems and links are included in PoB. Bandit rewards is kill all for the 2 points. Unique items are the following: 2 Poet's Pens, 6L "The Perfect Form", Chaos Impresence Amulet, Atziri's Step (+1 frenzy charges not needed, I also prefer th