Sorry chaps, I probably should have been clearer from the start! I'm trying to replicate a Kaboom in the workshop. I think I've got reasonably close to the shape but it's currently weighing in at about 3lb.
The thing is, my effort has 38mm edges, spine about 50ish. So considerably smaller than Chad's monster, yet still noticeably heavier.
It really demonstrates how much drier the wood that GN use is, compared to my homemade. I have to get more moisture out, probably another 5-6 ounces.