How to export to PDF only a specific layout within Alternate Layouts?

[Inélsòre]

I've got a document (musical score again) with page size 9x12 inches.

One orchestra would like the PDFs to be 10x13 inches. 

I could use Preview to manually rescale the PDFs or one utility that rescales PDFs but let's say I do not know about this and would like to do this within InDesign. 

I have read the InDesign Help chapter for Alternate Layout and created a new layout in 10x13 inches. Things look well apart from the fact that it now seems as if I had a single document made up of the two layouts flowing one after the other. In fact, when I export this to PDF, I have the 9x12 version followed by the 10x13 one in the same document.

In the Export PDF dialogue, I did not find any way to export just the 10x13 layout. 

Am I missing something really basic? Or how should one achieve this according to the InDesign gospel?! 

Thank you!

[James Gifford—NitroPress]

I'd say just scaling the print-out is the simplest, easiest, most foolproof and 95% unbeatable option.

Yes, there's always a more complex, "integral" method for something... but I'd bet this one orchestra would never know the difference. That's one of the things print scaling is for, after all. 🙂

[Inélsòre · Accepted solution]

Indeed, but I think I found something: the "Pages" dropdown menu in the Export PDF dialog.

With Liquid Rule set to Scale for all pages, alternate layout set to 10x13 and exporting that worked well.

One thing is that the batchexport script is not allowing this so it's manual export for each PDF. 

One thing that would require more care will be when I'll need to scale 232x305 mm to 230x305 mm, that is, only one side shrinks but the proportion of the music needs to be unchanged. I would need to understand more of the internals of how Liquid Rules work, or just make a new document lol...