I don't light on the surface. Nor am I looking for a chimney rest, but a flat un-seamed surface that is highly resistant, if not plain fire proof. Bricks mean seams and basically a platform, but may be the best alternative. Many years ago, the first pads I saw were semi rigid material that was about 1/4 inch thick. It was dark brown and I thought brilliant. I can't find the stuff now.
As to leaving a coal burning on the Weber and similar felt products. Try it. See what happens. Live coals burn through instantly. No it doesn't burn so yes it is fire resistant, just not melt resistant.
My chimney, which instantly melted through, no longer had coals in it.
Open to more material ideas.