I had mine done a few months ago. He used Flat Knit and the color: Charcoal. It too is a very close match...only a tiny bit darker; slightly noticeable some days and some days not at all. He ordered extra material and gave it to me, to do the pillars if ever needed or if I so choose.
When removing the original material he asked if I smoked in it. I said no, but I vape. He had me feel the foam backing and it was very tacky. He believes this is why the material began sagging...or "didn't help," I should say.