Did five more chapters of the Tribulations large-print layout—it went quicker this time with less drama, because I realized that part of the problem is that Scribus doesn’t automatically put soft returns after em-dashes. That’s always been A Thing with Scribus layouts, but it is especially a thing when the text is 18 points! I just kept an eye out for that issue when I was laying the text out, and I wound up only having to fix one after the layout was done (which didn’t screw anything up).
I’m totally not the most-advanced Scribus user out there (or any layout software, to be honest), but I’m wondering if there’s some way to set the preferences so that an em-dash and a hyphen are treated the same way—it would probably save me some time to figure that one out.