We do controlled, but we put out enough hay to last mostly until the next feeding, then put more hay out, keeps them from wasting it and picking through it. But the kind of hay feeder you use, will determin waste more than anything.
We only do mixed grass 2nd or 3rd cutting hay, only use alfalfa on lactating does.
We do free choice alfalfa hay (pure dairy grade as it's cheap around here), free choice mineral salt and free choice baking soda. The bucks get aluminum chloride mixed in their mineral salt, but no baking soda.
The alfalfa stems the goats don't eat gets thrown to the horses, so we don't have any waste.