Line a baking sheet with wax paper. Put 3/4 cup of the flour in a shallow bowl. In another shallow bowl, combine the yellow and white cornmeals with 1 teaspoon salt, 1/4 teaspoon pepper and the remaining 1/4 cup flour. In a third shallow bowl, beat the eggs with the milk. Dredge the catfish fillets, one at a time, in the flour; shake off any excess. Dip the fillets in the egg mixture and coat them completely with the cornmeal mixture. Set the fillets on the baking sheet and refrigerate until the coating is dry, at least 1 hour.