It might also be worth trying if the PDF reader in a Chrome/Chromium can use its “pages per sheet” option when using a print-to-PDF driver (included by default with Windows these days IIRC, likely available as an option at least on other OSs). You may lose some fidelity on things like images this way, depending on the options selected in the print to PDF driver.
` pdftk {{input.pdf}} cat {{1-10}} output {{output.pdf}} `
If you want to do multiple files you may want to burst them and recombine. If you are doing it for file size purposes there may be better options though, as I dont think there is any way to split in 500kB chunks for example.
There supposedely is a windows version [here](https://www.pdflabs.com/tools/pdftk-the-pdf-toolkit/). I haven't used it though.
But I've done it with Illustrator previously, at least.