Thanks much! Yep, I tested the Ubuntu Unity ISO a few months ago. I’ll try installing from it again soon.
Right now, I’m testing vanilla Ubuntu 18.04, but with Unity (and gtk3-nocsd) installed from Universe. Nautilus with gtk3-nocsd works okay, but looks a bit ugly. Even so, I suppose that, ugly or not, as others have suggested, it may be better to stick with Nautilus and other GNOME apps, which would keep consistency with previous releases.