PoE Keljhan builds

I liked the look of the Mahuxotl's lightning strike characters, but I love the speed and clear of KB/power siphon builds. So I drafted this up as a tanky clear speed wander: The idea is to abuse split projectiles and returning projectiles to ramp poison damage, and trigger flask charge on crit to sustain Dying sun. Looking for advice on how to push damage without sacrificing too much tank? Any other cool synergies along with sniper's mark + returning projectiles I should know?