Inspired by the 2 stone pizza grill from pizza therapy, I last night was successfully able to mimic this. I used a 16" round pizza stone which I bought from Primo ceramic grill. I placed this on the grill grates of a weber gas grill, I then placed 2 firebricks upright on each side leaving a small gap between them and the pizza stone. On top of the firebricks, I placed a rectangular 24" stone, in effect creating a hearth. I propped the grill top slightly open creating a convection draft. Pizzas cooked in under 4 minutes with good char bottom and top. Next time, I will try it and also cover the remaining open areas of the grill grate with tin foil, forcing more heat through the hearth chamber.