How many square feet of stratospheric ozone is destroyed by 1 fluid ounce of CFCs/freon?

Absolutely none, unless you are taking it above 35 km (115,000 ft.) and spraying it out where UVC radiation can knock off a Cl ion. There are no, repeat, no molecules of any CFC capable of diffusing up into the Stratosphere. Given enough energy to do so, the CFC will decompose and the constituents combine in other ways, long before the stratosphere can be reached.