What kind of rotary whip did you use? That glassy stuff is the worst, and a regular brush just skates over it. Sounds like you need the right tool to actually break it up.

Read somewhere that warming the boards first helps.

Thought that was rare till @lisayoung's squirrel story.

Wish I knew, that gold lasagna idea is genius though.

Remember they've actually been around a lot longer than that, like pushing ten years at least (I saw them at a trade show forever ago). The early ones were pretty flimsy, so your first guess was right for that version. The stuff they make now is a totally different material, way more glass in the mix. That's probably why your buddy's set worked so well, they finally got the recipe right after those first tries.