I am in the final planning stages of an ODK and incoprporating a Large Big Green Egg. The maximum diameter of the egg with the top closed is 21 inches. With the top open it is approximately 24 inches with the hinge. There will be a fixed wall behind the egg. For those who have incorpotated and egg with either a fixed wall behind it or a raised counter or bar behind the egg, what counter depth did you build?