Thanks! I am trying it now, quite nice, but it does a bit too much. Also the hidden posts are still left as empty lines, so it's not a real "hide" as implemented by HN.

Totally fair, and I don’t use the hide feature so I can’t speak to that. Since HN doesn’t offer a “hide” feature the best you’ll probably get is a way to remove that line have “$total - $hidden” links show on the page (like using the greasemonkey scripts).