Sea dog1,
I have found that with kokes the bottom really doesn't matter much, what matters is where there is feed. They feed mostly on plankton and where ever the plankton is where you will find them. Where I fish, which is a holding reservoir, the plankton is more prevalent where there is less current. I have found that the bite is better in February, but still catch them in the winter. They usually are schooling where there are plankton. Hopes this helps, and here's to tight lines all season.