Been running a 5/0 Circle hook (usually thin wire VMC but used to use stainless Mustads back when you could get them) on an Anchovy Special / Krippled since 1995. I then run a stinger being a 1/0 behind in the tail.
It works best with the biggest Anchovies (5.5 / 6 inch) that are well brined, and to make it work, you need TWO TOOTHPICKS. The first is to jam in where the line runs through for the teaser head to stop the teaser head from pulling down, and the second one is pushed up from behind the dorsal fin forward to set the bend. You snap off the "Jam pick" and you trim the "body pick" so it is not visible. A DRY TOOTHPICK IS A MUST FOR THE JAM PICK.
We fish Nootka in August, and sometimes the fish are a bit lazy, and simply bite off the tail. That is where the Stinger hook comes in. You can troll for 20 minutes and pull up to check the bait only to see 1/2 of an Anchovy from a short hit. Very frustrating. Because of the short distance between the main hook and the stinger, you have to use 50 pd test Florocarbon for the leader. Tie the main hook on with a snelled knot, leave a lot of trailing line, and then do a palomar knot for the stinger. Keep it a couple of inches from the main hook.
I used to live in Florida and all the offshore trollers pull circle hooks in the bill fish tournaments because these fish jump a lot. Using Barbless, you loose a lot, just like salmon.
The thing about circle hooks, is that it hooks in the top or bottom of the jaw, or the corner of the mouth. Once hooked, it is very very hard to lose the fish, except where you tear the jaw somehow. We have had 30 pd Springs jump half a dozen times 20 yards off the boat and still landed the fish, because a Circle Hook rotates when it digs in. To unhook the fish, you PUSH the hook inward and turn, then it slides out.
We have switched over all our Coyote spoons to a 5/0, as well as all of our hootchies. I have not had a lot of luck pulling plugs in Nootka, so I cannot comment on the effectiveness of Circle Hooks on Plugs, but for spoons and hootchies, it works fantastic.
For sizing, you do have to go a full two sizes or more because the hook set depends on the gap between the tip and the shank of the hook. This is the Gap that slides into the jaw. Because fish instinctively hit and turn, it is at that second where the fish turns that the point sticks in and starts to do the rotation.
Given the competition at Nootka, you want to land every fish that hits, because it will be a good fish, and because you may only have a few hits a day. A Circle hook does give the advantage on the larger fish, especially when they go airborne, so I hope some of you try experimenting with Circle hooks this year.
Drewski