Combine the seasonings mix ingredients in a small bowl. Sprinkle each side of each fillet evenly with 1/2 teaspoon of this mixture. Preheat a 10-inch skillet over high heat to 400°, about 5 minutes. Spray the top side of each fillet evenly with vegetable cooking spray. Place the fillets, two at a time (sprayed side down), in the skillet, reduce the heat to medium, and cook 2 minutes. Turn the fillets over and cook until done, about 2 minutes more. Remove the cooked fillets, wipe the skillet clean, bring the heat back to 400°, and repeat the process with the remaining fillets.