I remember a story about a book author (may have been Tim Ferris) printing book covers, placing them in libraries, and observing how many people picked out the book. That story stuck with me and I extrapolate from it for new products.
Care to explain how would observing that work in practice? There's no ISBN, so you can't track rentals. QR or URL would not give "real" results.
You sit on a chair in the library or book store isle next to where you put your “book”.