What is the shape of the body of water? Are you able to seine it to move the fish to one area to get the undesirables out and leave the rest in?

You may have plenty of forage fish for your predators - you say that the water boils around your 3 feeders when they go off.

What size catfish are you getting? 300 lbs may be too many especially if they are 4" fingerlings.

Also, do you have both structure and cover in your pond? A place where predator fish can set up to pick off forage fish?

In addition to stocking you may want to consider building out habitats for forage fish to congregate in, and areas with cover and structure for predator fish to prey upon forage fish. These will give you target fishing areas.