So I now have it (for some variable number of pages books, that are ganged together, and have different stocks per page) proving the records, ganging them together, and saving the file. Or I would, but it’s thing random errors. I think I need to bounce the street in the AM.
Now to get it to read the hidden code for what sheet gets printed on what.
Also, I really wish it played nicer with closing the PDF I’m mangling.