[KajMagnus]

How nice, I'm interested in doing precisely that, for lazy-loading a commenting system I've developed (Disqus alt).

> My page weight varies slightly, but I went from around 700KB, to 1.5MB - Disqus was larger than my entire blog post

That's what I've seen too, i.e. that Disqus is about 700 - 800 kb. — There're Commento, about 11 kb instead: https://commento.io, and Talkyard, 150 kb instead: https://www.talkyard.io/blog-comments (I'm developing Talkyard). Both support Disqus comments import.

You've thought about quite a lot of things: :- )

    // load comments for search engines to index
    ...
    // load comments if URL hash contains #comment
    ...

Probably I'd have forgotten both those two things, some time in the future when I'll implement lazy-load by default for Talkyard.