This can't be fully correct, though, at least for my (as-remote-as-it-gets) area. My father was born in '52 and had to learn it in school here. He still writes the small 'z' in Sütterlin, and it looks really nice.

Hmm, I believe you. The article also says "Sütterlin continued to be taught in some German schools until the 1970s but no longer as the primary script.[citation needed]"

Looks similar to the cursive z I learned - I guess in the late 70's/early 80's - in Scotland. It's still in my signature, although that's a right scrawl.