Kunan,
There are three ways to effectively fish a kwikfish and they all depend on depth, current and length of the run.
First, if you're fishing deeper water 8-15 feet I'd recommend a jet diver and run that off a sliding dropper that's about 5-8" long with a minimum 48" leader. Second would be to anchor in the tops of the run above the fish and backbounce the kwikfish off a 3-4 foot dropper and work them back into the hole. Your dropper length will be determined by current and size of kwikfish, use enough dropper to keep the plug from diving into the rocks.
Third would be to flat-line the plugs which it sounds like you were doing, and figure that a K15 will dive around 8-10 feet. I rarely flat-line a kwikfish though as you don't have confidence in depth with fluctuating currents.
Some problems you may have ran into in why you weren't catching fish would be line size and the size of kwikfish you were running. I'd recommend nothing larger than 20# test but prefer in lower clear water to run 12-15 with the kwikfish.
As an opinion, my first choice of tactics up there would be to backbounce or bobber fish eggs and eggs/shrimp then back it up with your wrapped kwikfish or herring.
Hope this helps,
Keith
