Argh! I need to check the number of pages before I post! Sorry. After reading the first page or so, I chimed in ... not realizing there were another 7 or so pages of posts to go.
One fellow in a different forum (I think) did a pizza stone on firebricks set on their edge lengthwise. It raised the pizza stone up toward the top of the Weber's dome lid. He reported very good results in terms of getting the toppings to cook at the same time the bottom of his crust did. When smoking meats with my Weber/Smokenator setup, I monitored dorm temperatures closely at the beginning. Dome temperatures were higher than the food grate temperatures by 50 degrees Fahrenheit at least. It might be worth trying raising your cooking surface nearer the top of your copper dome.