Isn't it ironic that my Dr. says stay away from salt, but the fish seem to love it!
Seriously, I'm convinced the heavy salt in both the Ika and the Senko is the reason fish eat those baits regularly.
I don't mean just hit, I mean eat, as in swallow.
I add 1oz of salt for 4oz of plastic, mostly to get the casting weight I want, but also to get the fish to hold the lure longer. That amount of fine Del's salt doesn't make the baits too opaque.
I have fish eat my Zoom lizards, too, and Robo worms, but not nearly as often. Fish will hold an Ika or Senko so long that I have been able to gently lead them out of cover before I set the hook. They don' want to let go!
I pinch down the barb on the 4/0 hooks I use for them, because they get swallowed so quickly sometimes that gut hooking is a problem, and pinching down the barb makes turning and removing the hook a breeze. I seldom lose a fish with that big hook, even when they jump, as long as I keep good rod tension on them.
I use salt in my Ika knockoffs, and use softener to keep the plastic soft. With a thick piece of plastic, like an Ika body, softness helps with good hooksets.