The formula for how many fluid ounces of Berryman Tire Seal-R to add to a moderate speed tire is width of tire X height of tire X 0.04. For slower speed applications like yours, we recommend using approximately twice that much. For your larger size tires, we recommend using 12 fl oz per tire. For the smaller size tires, we suggest using about 4 fl oz per tire. One quart of our Tire Seal-R (part #1332) would just about be perfect to treat all four tires.