Yes , each frame had to be good to bring it down to a book of 60 prints
I used to provide an album with 12 pages in my standard package.
I would then work with the clients in their decision respecting how many pages consisted of one 8"x10", two 5"x7" or four 4"x5" prints.
Clients could order extra pages, and often did.
Clients could order extra prints, and often did.
And clients could buy some or all of the 6"x6" proofs, and often did.
It worked in the context of the Vancouver area wedding market.
And wouldn't work in the current market.
One caveat though - I tend to bring a camera when I attend a wedding as a guest. The last time I did so with a medium format camera (a Mamiya 645 Pro), I got my old pro lab to develop and give me 4"x5" proofs. The bride and groom were considerably more impressed with my "proofs" than the digital and printed proofs they received from the photographer they hired - their comment about mine: "they are so clear!". That photographer's work was quite decent, but it was clear that they had economized on the proofs they delivered. I expect that approach to proofs is a consequence of the current market forces.