I switched to a single large siwash on my hoochies on the ocean a few years ago. This is how most commercial trollers out here fish them, and I'm a big advocate of taking advice from the folks who literally have to put fish in the boat to make money.
We call this setup "the leash" because once a fish is hooked, it's not coming off. I'm not sure if the initial hookup ratio is any better or worse than a standard two hook rig, but I can say with confidence that once hooked, we lose far fewer fish with that setup.
I am a total believer in rigging that way, however I don't think I'd run that setup in the sound, at least how I run it on the ocean with a very large hook. Out here we don't release "wild" chinook. Any chinook of legal size may be retained. I find running a large single J hook like that leads to many more fish that are impaled in a way that I wouldn't want to release them. Brained, eyeballed, and other such wounds occur often enough that I don't think I'd feel right about fishing that setup in any sort of selective fishery. I suppose you could run a smaller hook to help alleviate some of that, but IMO running a smaller hook might start to diminish the advantage of running it that way to begin with, but that's just a guess. I've never tried it with a smaller hook so it may work just fine in the sound.
Just my two cents.