Like so many things in Dorico, it's all in the setup. This method does work. The trick is in setting up the master page and making it the default master page for the project. I had to watch that section of the video several times, and try it several times, before I got it right. I had several separate projects with various sizes of blank staff paper, and I can now combine them into a single project. Very cool - if you get the steps *exactly* right!