Dark/Dark is a very different beast than Fire/Storm. For one, /Dark has an endurance management tool, while both Fire and Storm are extremely endurance heavy sets.
For endurance, I recommend panacea/miracle/numina's uniques in health by 27 with a performance shifter proc and a generic or performance shifter end mod in stamina.
I would start Hot Feet with an accuracy and then 2 end redux. Tornado and Lightning Storm also need some good end redux slotted.
It hurts me to say this, but you can't spam Fire Cages.
I've always loved the idea of Fire/Storm, and I made one on live several times, but never got very far, mostly because of endurance issues.