I'm not sure you could get sexed CC. As long as your original stocking number is fairly low, and you only restock as needed, your predators should be able to control most CC offspring when they are still small. Just don't practice catch and release on your CC, or you may have trouble getting a second chance, though I caught mine repeatedly in my personal pond using only chicken liver as bait. My CC never bit on anything else.
Stacking tires with no more than 2" gaps (top and sides) using 1.5" PVC pipe as spacers will make some nice safe havens for prey fish to hang in while predators stalk around them.
