I'm new to this, but it seems a 90% solution would be as follows:
A kitbash containing: instructions on how to add registration marks to the existing PDFs (I do this all the time, with simple transparent template cut-and-paste) and GSDs that use those marks.
Sure, some will be outside the marks (and won't get cut), but 90%+ will! And no need to re-distribute the bits.
From what I read on the threads, this is probably what WWG means by not meeting "top quality" - but fans don't need 100% quality, we just need as much help as we can possibly get.
[Yes, I know some pages won't work that way, as art overlaps the normal reg mark positions - that's fine. We'll hand-cut those pages..
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OldSchoolDM [NewSchoolPapercrafter]