I'm looking for a quantity recipe for Lemon bars. I have lots of recipes, but they're all for small pans, 8x8". I need a much larger quantity. I don't want to just double/triple the recipe. Also, when do you cut them, hot or cold? If I wait till they're cold, I break the top surface and they look terrible. But you have to let them set a bit, but I don't want to break the surface too much. Thanks.