Salmon Fishing - Swivels on Spoons?

[Boatless]

I have searched this forum but I have not found the specific answer to the question I have - adding swivels to spoons. But my apologies if I missed something and this topic was already covered.

Here is my question - while fishing for salmon from shore/pier using spoons (Little Celos) do some of you add additional split rings and swivels? My search on other forums turned up many different combinations:
-use the spoon out of the box (tie direct to the lure)
-add split ring and tie to it
-add split ring and swivel
-add split ring and swivel and add another swivel for the hook

I have read here that tying directly to a spoon could cause the line to be cut on the sharp edge of the hole - so, adding a spilt ring makes sense to me.

However, I am wondering how critical swivels are - i have seen that when I pull the spoon out of the water after reeling it in that it will spin itself out until the line twist has relaxed.

So, a swivel makes certain amount of sense but a swivel on the hook side?

Most importantly, what happens to the action of the lure if I add a swivel? I have tried swivels and I can feel less action on my retrieves and so I am wondering if I am losing lure action. Thank you,