I have tried various small treble trailer hooks for freshwater using the 5 and 6" swimbaits. It always seemed to be more of an annoyance than anything. If you are getting short bit on swimbaits by halibut, you might just go down a size. You might also be getting bit by other fish besides halibut. I've had times in the SB Harbor where every cast was ronkie bit even using 5.5 inch swimbaits. Halibut will leave sharp well defined lines in the plastic. Ronkies will leave a small half circle of fuzzy bite marks. Ronkies almost always bite the bait in the belly as well.

Try a 4" bait with a 1/2oz head for the flatties. If the fish are bigger than 22" they should have no problem eating that bait.