Really drawn to the idea of storing the final recommendations in a separate file. Didn't write it that way initially because most SSGs handle "data" files in their own unique way, and one of my goals was to be as "light touch" as possible. But I guess that could be solved with some config options (set `path/to/data.json` or similar).
I agree that "79% match" doesn't mean anything on it's own (and is, yes, totally arbitrary in a lot of ways), but it does provide some context when browsing across the whole site. It's a way to indicate that a "90% match" is more similar than a "60% match". Felt like useful info to me, so that's why I included it.
As for "why only top two?" - I'm constantly paranoid about adding too many bells and whistles to my blog and overloading the patience of whoever's taken the time to read. If I had official rules, they'd read "no carousels, and as few Calls To Action on a page as possible". I'm not super strict about it, but 1 recommendation felt too stingy and 3 felt like too many.
BM25 is new to me, and I'm mostly a n00b when it comes to "proper" search. But I'll definitely do some more reading. Currently setting up a head-to-head with an embedding index and a fuzzy-search library, but don't have any scientific way to measure the results. Sounds like you may have pointed me in the direction of a missing piece of the puzzle. Thanks!