Bought recently a set of pans for a checkered look on my cake. It says it has 3 9-in pans that are 1.5in high, and that I will need 10 cups of batter for them. How much is this? I would like to do a recipe that states is enough for two 9in diameter cake pans, but they don´t specify the height. How can I adjust this recipe to fit in my pans? Maybe just double it and use the excess batter for cupcakes or whatever?