It would come in handy for the Hermetic Merkavah course too.
It measures 5.5 or 6 inches across, I can't remember and the ruler is ALL THE WAY in the other room. I'm including the crystal ball stand I made with it, but you'll have to supply your own spherical stone to put on it. The pic below shows MY stone on it, and you totally can't have it.
$45 buys this Table of Practice and scrying stone stand for your very own. If you're interested, drop me a line. I've only got one, so it's first come, first served.
(Coca-Cola, protractor, and keyboard not included.)