Hank and Adam, I don't think Jeff could spell it out any clearer. This design, as it stands, is not viable. You're either talking heat from below, with the top of the pizza never getting properly baked or you're talking heat source on the side, which results in an 8" or smaller pizza.
If you guys want to make 8" pizzas, go for it, but, if you want to save yourself a lot of angst, use your webber and build an LBE. Getting a Neapolitan pizza out of an LBE is no easy task, but it's got a much better track record than this. At least with an LBE, you've got a fighting chance.