In a large bowl, combine 1 gallon of the milk, the sugar, butter, vanilla and mix. Use a whisk to make sure that the sugar is mixed well.
In a separate container, combine the remaining 1/8 gallon milk, cornstarch and flour. Blend until creamy and smooth with no lumps. Set aside.
In a saucepan, bring the milk/sugar filling mixture to a boil. Using a wire whisk, blend in enough of the milk/cornstarch mixture and cook until the mixture is thick enough that you can see the trails in the milk when the whisk is pulled out and the mixture is not runny anymore. You may not need all of the thickener, this all depends on the humidity of the room.
While the filling is still warm, add the coconut. Pour into pre-cooked pie shells. Take time to cool and set-up before adding topping.
For the topping:
Preheat the oven to 350 degrees F.
Beat the egg whites until they form stiff peaks. Then, mix in the sugar and stabilizer until creamy smooth.
Top the pies with coconut. Place in the oven until desired color brown is achieved, about 6 minutes.