It looks like a ball tool is not the best choice for carving into plaster, simply because you can’t carve into plaster with a ball; you need a knife of some kind. At this point it looks like a small drill bit might actually do it, though whether this is true won’t be known until 2 days later when I make a test cast.
And while doing a pilot “drill” with the needle tool looks like an attractive idea, it looks like it’s a really bad idea because when you hear that reassuring “pop” sound the needle has already gone too far into the plaster. So how do I do the pilot drill with something else? I’m not too sure. And I don’t really like the idea of making more and more test moulds. I don’t have time. I won’t have access to the shops very soon.