In my experience in rivers,spoons are an effective lure for both coho and chinook as well as steelhead. They like plugs are mainly an agression stimulator.
For chinook I like to use them in resting pools at first light in the first pool above heavy water.Chinook on arriving in such pools will circle and attack any foreign species including spoons ;that are present.
For coho a species that will chase rapidly retrieved lures I like to fish spoons in deeper slow pools and along undercut backs with slack water.
For steelhead they are strictly stimulators which can be dead drifted with short swings like escaping minnows and fry. I fish them under a float using a lift and drop action.
Sometimes they work ,often they dont.