We recently had an oven built down here on the Pacific coast of Mexico where traditional mud ovens have been used forever. It is a large oven - diameter of the floor is 63 inches and height of dome is 60 inches. Our opening is about 27.5 inches by 12 inches and there is not a chimney but there is a small circular opening about 6 inches in diameter on the side just above the floor. Once we get the oven up to temperature we have been splitting the fire into two and moving to both sides of the oven. The problem is that the floor in the center for cooking is dropping in temperature very quickly and the pizzas are not crisping up on the bottom. Any suggestions on how to control this better?