How many to stock? Like all things ponds, that depends. I don't know what the conversion rate is for catfish, but a LMB needs 10# of fish to put on 1 pound.
Using that figure, it'd be easy to figure out how many forage fish you had to add.
Just remember that lots of fish and fish food = high nutrient loading, which leads to algae problems or submerged weed problems if you don't get a good bloom established to block the sunlight from reaching the pond bottom.
Without pushing it too much, if you have supplemental feeding and a good aeration system, you could probably have 500# of fish per acre. Figure 1:10 by weight predator to prey. Or 1:20 for faster predator growth.