Hiding staves that leads to part-filled pages

Uh-oh, I’m back again. Sorry about that.
I set up a score to hide unused staves with exceptions. It worked throughout except on the middle page shown in the screen shot and once more further through the score. The only reason I can think of is that the very few staves made Dorico think or hope that another chunk of staves of a similar number would follow and would appear as a second “system?” beneath.

Point is, I’d be happy enough to ‘open out’ these staves in Engrave. But have I missed some setting that would do that automatically for me?

And if I do have to open them out, can I copy the separation settings to the other page this happens in the score.

The zoom level in the screenshot was set to 75% to show several pages together.

Thank you for your time.

Layout Options > Vertical Spacing > Justify distance between staves and systems when frame is at least [n]% full.

By default this is set to 60% full. If you go to Engrave mode, then click on the Staff Spacing tool in the left panel, you’ll see a percentage at the bottom of each page. I’m guessing it’s slightly above 60% on the “open” pages and slightly below on the “closed” pages.

You can “open out” these pages globally by setting that first threshold to something less than 60%. In some circumstances it may make more sense to squish two systems onto a page.

That’s done it.
Thank you very much.