Wow, you're very patient to stick with something that needs that much precision. They look very professional to me. Have you considered taking the folios to a book printer and asking if they could trim the edges for a tiny fee or for free?
It may not need to be a book printer, any local press may have the right equipment.
I think the real art is in the design and creation of the book, a little trim at the end by someone else I wouldn't consider a cheat. They're lovely trimmed or not!