Thanks for the links Pete, some interesting reading material there.
I have done a few pizzas on the gas bbq ( although my bbq is natural gas ) ( it doesn't seem to be as hot as my
old propane bbq )
When I did mine, I put down some tiles first, ( the unglazed quarry tiles ) then my pizza stone on top of those.
Results were ok, but I found it dried out my pizza, because too much heat was leaving the bbq, so I found the dough
to be a tad dry, ( and it took more around the 12 min mark to do a pizza I usually get done in 8 mins in the oven ),
having said that, what does elevating the stone off the rack of the bbq do ?, I'm not really understanding the concept.
I'm guessing there is an airflow of hot "convection" type hot air that is coming into play here, but without the top piece that Willard
had added to this pizza machine, I don't see how this other "topless" version would work that well. I am beginning to see that Willard's version is basically capturing the hot air, and it is being reflected down onto the pizza, but the model in your links does not have that capability.
That product has been around for a long time, as noted by this geriatric post: http://www.pizzamaking.com/forum/index.php/topic,259.msg4364.html#msg4364 (Reply 3). For a more recent discourse, see http://www.pizzamaking.com/forum/index.php/topic,4948.msg41881.html#msg41881.