Kingfish have tough mouths. The hook size is not critical, but having sharp hooks is. Always use wire leader for kingfish. Kings have some of the sharpest teeth, so landing one while using monofilament leaders is strictly a matter of luck. Leaders for kingfish need not be long, preferably no longer than three or four feet.
Longer leaders make gaffing harder by allowing fish to stay farther away from the boat.
Never use shiny swivels when rigging for kingfish. Kings will bite a silver swivel, which means a severed line. You ll lose a lot of tackle and hooked fish if you don t use black swivels. Tackle for kingfish should be on the light side. 30-pound test will get plenty of fight out of the fish, yet is strong enough to whip all but the largest.