I have not used this specific tool, but have used https://community.coherentpdf.com/ for the cropping/rescaling. And in general "printing" (posters) is what I have used it for (books make sense though as well).
Depending on the site and what you are doing it may auto-rescale, I try to make it exact though just to prevent any nonsense on their end (and in Adobe PDF you can print tile to check it out as well in actual size).
Depending on the site and what you are doing it may auto-rescale, I try to make it exact though just to prevent any nonsense on their end (and in Adobe PDF you can print tile to check it out as well in actual size).