I used Apple's Pages word processor. I set up the page setup to have the metrics of each individual eighth-of-a-page, then then made an Automator script to convert the PDF that produces into a series of .png files, which I then lay out in another document with pre-set page positions and rotations. I then export that as PDF.
That way, I have two PDF's: one that can be read by a PDF reader and it will flow in the way people expect, and one in a foldable format that will fold correctly.