Got it. So you cut a strip out of an oil drum and are using it as a wall. I like that idea.
There's not a huge amount of information floating around regarding how Jeff built his Frankenweber, and, to make matters worse, he changed his design a few times, but, as far as I know, he never used the weber lid as the inner dome, but, rather, used the weber lid as a mold to cast his dome, filling the lid entirely with some kind of refractory mix.
By filling the lid, he reduced his final dome height, which is critical in any bottom/side heat scenario. Without the lower dome, you don't get as much radiative impact and the top of the pizza tends to bake much slower than the bottom.