I am replacing my el-cheapo stone. It broke when the wife turned on
the electric burner it was sitting on. I do most of my baking (pizza
and bread) on the gas grill outside (Weber Silver B). The el-cheapo
stone had no problems with that directly on the grill. I am
considering a Fibrament stone, however they say don't put it directly
on the grill. They offer a BBQ version that comes with a metal pan for
an additional $15. The BBQ version only comes in round.

If my old stone handled the gas grill OK, why wouldn't a Fibrament?

If the Fibrament really does need something between it and the grill
surface, why wouldn't a cheap cookie sheet or some unglazed quarry
tiles suffice for this?

Slightly OT: If I decide to just use the quarry tiles (with no
Fibrament stone), do I bake directly on them or put a baking sheet on
the tiles?

Thanks,

Todd K.