14, 12, 10 is way more servings than what the customer wants. I also read a lot that a 6 inch looks best for the top tier. A 10 inch on top would look very short and squatty. If you did a 6, 8, 10 you would have 74 servings which the customer would pay for even though they only need 60. You just can't get exact matches always. Then you wouldn't need any dummies.