For this exercise, I decided I'd better thin out the couverture a bit. White chocolate can be vexingly thick and difficult to work with. So I fished out a few ounces of cocoa butter and nuked away until it was liquid. Then I melted the white chocolate and mixed in the heated cocoa butter until the chocolate was the consistency I wanted. I set the cocoa butter aside to be re-tempered and stored, and then I tempered the white chocolate on my slab.
spread it evenly, tapped out the bubbles, and waited for it to set up enough to scrape down. Learning the proper timing on this takes practice, as evidenced by the fact that I didn't do it quite right this first time. I scraped, and some of the chocolate came away from the circles I was trying to create. I'm not sure if this is because I hadn't let the couverture set up enough, or because I let it set up too much. I'll need to investigate. At any rate, I peeled off the stencil and after the chocolate had set, I saw that many of the little discs came out well enough to use for my assignment. Some were raggedy-edged, and I cut them down into sickle moons. If I want to do this on purpose next time, I'll remember to use my circle cutter when the chocolate hasn't fully set. Otherwise, it cracks and you lose most of your hard work.
Notes for next time: Thin the white chocolate more; figure out the correct timing for scraping down the stencil.