I have no experience with JWD coal loads, so I have no comment about the quality or fitment. That said, if commercial coal loads don’t work for you, or especially if you’re loading an entire fleet of open hoppers, which can become cost-prohibitive, consider black sand from the art store. It will even give you those shiny reflections like real coal. Glue it down over a core made from balsa wood or foam, and “Bam!” You’re done.
DFF