Preheat oven to 425°F. Put 1/4 cup flour, salt and pepper in shallow dish or pie plate. In another shallow dish or pie plate, whisk eggs, horseradish, mayonnaise, and cayenne pepper. Whisk in 5 tbsp flour until mixture is smooth. Put seasoned bread crumbs in third shallow dish or pie plate. Dry fish with paper towel and season with salt and pepper. Working with one fillet at a time, dredge in flour and gently shake off excess. Coat with egg mixture. Coat all sides with breadcrumb mixture. Spray wire rack with nonstick cooking spray. Transfer breaded fish to wire rack. Place rack on cookie sheet. Bake for 18 to 25 minutes.