Can I make a PDF generated file fit into a single page?

We're trying to make a PDF using Workflow Automation, but we want to remove the page breaks. We've been trying to do it by setting Custom Paper & Orientation sizes with a big enough height to fit the whole document.

Problem is that, for some reason, a blank space always appears at the end of the document, causing it to look bad or breaking the document into 2 big pages.

Is there another way to do this?