Someone enquired if I was aware that Google Custom Search “Sites” control panel needs to have a distinctive fragment of an URL entered if it’s to seek accurately for a match. This is to do with checking if an URL is already in the site index. Google Custom Search will happily add a duplicate if you let it, especially if you just check against a full URL. Yes, I’m fully aware of this feature, and that it’s case-sensitive — and so only search for a distinctive fragment of an URL, before adding it to the site index.
I am also cutting back the URL slightly if needed, to give Google a slightly wider “spread” in what it picks up from that URL. Ideally, I’m seeking out just the URL that holds the articles (which is often very different from the main journal URL).