I haven't re-read this entire thread, and I may have said this before, but here goes.
Are you interested in finding blank Scott International pages -- with no printing at all on them, not even a border? Your remark "maybe better than shopping around for custom-sized paper to fit the Scott albums" suggested you were. If so, contact this website which sells Scott International sized blank paper with no border and holes punched for that album for 25c a page. It also sells the same pages printed for you with Steiner page layouts for slightly more.
https://www.albumpages.net/That way your album is not a mixture of different-sized pages but would look uniform AND be comprehensive, not the usual partially complete Scott International pages.
I pretty such I mentioned this previously, but Subway Stamp Shop also sells reprints of Scott International brown album pages which are complete for all stamps 1840-1940 which would cover a great deal of any worldwide collection and be the correct page size and so on. They call them their Vintage Reproduction pages and they're exact copies of the original Scott brown album International album pages which fit those binders.
https://subwaystamp.com/collections/vintage-pages