Do you think using a small ball swivel about 2 feet above a spoon will stop the spinning? It may also prevent line twist. I was thinking that line twist comes from reeling in fish vertically; think about it, the fish is spinning as you reel him in.
How about using a snap swivel with a spoon.? I think they recommend this in open water. I read an article in PA Angler where the author put a ring and a small ball swivel on all of his spoons; though it seems like a lot of work.