I believe the el diablo is a dual wanding unit. However, you do need tobpau attention to how much hose you are putting on each line. 200 feet on each side would be fine but not over that. No it isnt like a
vortex where both lines can br as long as you would like them to be. But not too many people have commercial that big.
At least where i am located, if you cant reach the entire building with 300 feet of hose you missed a door. Buildings arround here have multiple doors for fire codes so even if i have to run 300 feet from the front door i can move to a side door or a back door and get the rest.