while bringing my weber performer home the heat diffuser blew out of the back of the truck. I thought it was under the grate. DOH!! being a flimsy piece of sheet metal it was no great loss. it looks like the easiest replacement would be a 20" pizza pan which in the 22.5 grill would leave a 3/4" gap around the edge same as the original. what i'm wondering is whether a pizza screen would work? it's basically a pizza pan with holes in it to help crisp up the pizza crust. or-would this let too much direct heat through? 17" is the biggest I've found locally. would that leave too big a gap? online, the shipping is twice the cost of the pan!