Minimal size adjustments to individual pages

I’m working on music layout in Dorico and need to create fold-out pages (gatefolds) in some instrumental parts to optimize page turns. In a project I previously made in Finale, I could slightly reduce the width of an individual page in a spread (e.g., from 210 mm to 209 mm in A4), so it folded neatly without creasing. I believe Finale allowed changing the size of individual pages.

As far as I understand, Dorico doesn’t allow resizing a single page within a layout. I have an idea to use the Print function and print the pages that need to be narrower at a different size. I don’t see this option directly in Dorico, so I plan to set a “Custom Page Size” in CutePDF, for example. Then, I’ll merge the normal and narrower pages into a single document.

Does anyone have a better, faster, or easier workflow for making minimal size adjustments to individual pages in Dorico?

It all depends on how the sheets are being printed, folded and trimmed; and what the printer/binder needs to achieve the fold-out.

There’s nothing to stop the fold-out being trimmed short regardless of the page size. (Usually, it’s a bit more than 1mm, as most trimming is +/- 1.5mm anyway.)

Are you using Crop marks?

I just need to provide a PDF with clean page sizes (no crop marks needed); the final work is being done by a graphic designer at the publishing house.

If you have a PDF utility app, that should be able to trim a single page. (Though of course if they’re printing a narrow page onto A4 paper anyway, they’ll still need to trim it short.)

All pages in printing company are being cut anyway. Thank you @benwiggy, what are your PDF utility apps of choice?