A surface iron like a Tady 45 weighs about 3 oz and swims just below the surface on a medium retreive. A Salas 6xJr weighs about 4.5 oz and is a heavy, yoyo iron. Drop it to the bottom (or below where you think the fish are holding) and crank like crazy. A reel with a 6:1 gear ratio is good for yoyoing. When your iron is back to the surface (or above where you think the fish are holding) let it back down and repeat. That's why it's called yoyoing. If your jig stops moving it's in a fishes mouth... crank even harder and set the hook!
Having both is a good thing.
