The idea that the fish don't care what you put in front of them if it's presented properly runs very contrary to my experience. Sometimes, choice of spoon makes all the difference. I fish most often on a tack in Haida Gwaii where I know most of the other trollers, especially last season. As we meet going up and down the tack, I exchange information (not on the radio) with several "partners", including a couple of charter guys, .
One day about 10 years ago, with maybe 25 boats working a couple of miles of coastline and getting no results, I figured I'd try a spoon I'd seen recommended on this forum in a "Ten Lures You Need in Your Tacklebox" thread. Aside from the fishermen running anchovies and cut-plug herring, guys using spoons were trolling 5-6" Clendon-Stewarts and the like, and some had even bigger Wonder Spoons and other commercial-type hardware. Most of that summer, a 5 1/2" Clendon-Stewart in brass/nickel had been killer. However, that "10 Lures" thread had several recommendations for the 3.5" GreenGlo Coyote Spoon, so I'd ordered a few, and I put one on behind a flasher.
Bingo! As soon as the spoon was down, we were on, and as soon as we had two down, we limited out fast. There was no bite on for anyone else, so as we headed out to jig, I passed one Coyote each to three other boats, on condition that I got them back! The result was that four boats limited out, with all but one fish caught on the Coyotes, while the rest of the fleet had a very scratchy day, with only a few fish caught by the other boats. One unsuccessful boat had some 3.5" Coyotes in Cop Car, and rigged them like I told him we were rigged. Zilch.
Since other boats that were successful on the GreenGlos were of various types and sizes, with individual variations in rigging, speed, and tack, it wasn't a bunch of cloned presentations producing their results. The hardware they had down on the other side of their boats didn't produce. It was the spoon. Many, many times, it's the spoon, or the hoochie. Any one who has trolled much has seen one spoon get scarred, chewed and bent beyond recognition on multiple trips, while identical spoons on the other side of the boat get badly outfished. Show me a salmon fisherman who hasn't mourned like he lost a loved one when that Old Faithful spoon or plug was finally lost, and I'll show you a guy who needs to fish more often!
The Green-Glo Coyote was hot for the rest of that season, and did as well as anything the next year, but it's never been the same since. The last couple of years, I drop a 5" alewife imitation made in the Great Lakes area first, but if I don't feel like it's trying hard enough, it sits on the bench while we try to find something better, with a little help from our friends.
The upshot is that compared to even a decade ago, the tendency I've seen is toward smaller spoons than the old commercial-troller hardware. If you'd told me 20 years ago that sometimes I'd be running a 3.5" spoon at 60 feet without a flasher, and knocking them dead, I'd have thought you were crazy. Maybe the bait is generally smaller due to ocean conditions or herring over-fishing, and certainly the salmon are on-average smaller. Whatever the reason, the idea that just altering presentation while using the same spoon is better than giving the initial spoon a fair chance, then trying to find what's hot, runs counter to my experience.