What Brad really means here, is save yourself a LOT of head ache and work, and pay someone to built the whole cage.
I've watched Brad do it before, and I'm all for giving stuff a go myself... But bugger that idea!
As for manifolds, I'm going to be building some for myself soon too, I've watched a manifold builder work, and it's worth a crack yourself if you're handy with some metal work gear. As for doing manifold building as a job... Yeah... No thanks! LOL