Sam,
I tried your tool and it works great. The only problem is that the PDF output is blank starting at page 1000 and page turns get really slow (several seconds) later on. The same thing happened with custom PDF's I printed from manybooks.net, but it seems to be a problem with the files and not the reader as someone else made a large PDF file that works fine (see this post
https://www.mobileread.com/forums/sho...4984#post44984 ).