I had a pizza stone for the last few years and it worked well as a heat defuser, however it recently broke while in use. It broke right along the line of the burner. I have tried tiles which also broke in use. I am now using a 10" Lodge cast iron round griddle that I hacksawed the handle off of. It seems to be working well.........I don't think it will break, but time will tell.
2012 321RLTS Eagle
2011 F350 CC SB