Thanks for your help. When I read your message, I said to myself, "OF course I've been pressing the 'Apply' button." But I went into Calibre again anyway to make sure...
As it turns out, there's an "Apply" button at the bottom of the window, and a second "Apply" button at the top. I hadn't noticed the top one.
Now that I've got it figured out, it's working.
Thanks again for your help!
