I have a hunch I have seen something about this. I think you can use a CSS calc to get the number of pages to do page X of Y, given that you can test if the page number for being odd or even. Then force a page break if needed, which adds another page and places the content on that next page ie the odd or even one. But I am not sure.
Printing
I would like to reserve the possibility to generate a final book, but it is not yet my intention, however I may need to “give the book away”
in the end. Not that this necessarily stops me achieving what I want to do with this book, but that is another story 
The main thing I want is tools to help write and organise.
Also tools to assist with draft sections, ensuring I revisit and take them out of preliminary draft, then later out of draft altogether. Similarly with their placement in the book.
- Of course I need footnotes, links, book and authors references etc… so need them to work with streams. This may be the hard part.
I am currently thinking I may base the book on a tiddler for each chapter, then using streams divide it into sections and smaller units as desired, however ultimately collapsing the resulting hierarchy into a flatter one (primarily Chapters and Sections).
I think I would like to see the automatic streams tiddlers get renamed into searchable titles, allowing me to search based on title only, and/or content. Then if something does not belong, pulling it out of the heirachy, and keeping it for placement elsewhere if needed.
Like essays, I think I need to later present introduction and conclusions on chapters and sections that telegraphs what is to come, or summarises susinctly (yes I must fix my spelling and grammer checker) as I am prolific with typos.
At the moment I need ideas about how brainstorm then to write and structure a book.