I had seen that a while ago so I went back to try it again.
I had assumed the bucket name was not needed anymore before the objects.dreamhost.com but had never gotten it to work. But I figured that was the only thing I wasn't doing the same so I gave it a go.
And it works! So cool. That's what I get for assuming, right?
I have to keep reminding myself that cloud stuff is not at all like FTP stuff. I rather dislike cloud storage but it is a necessary evil for proper offsite backup.
Oh, and other than a few steps being different and the screenshots of course being different, after a year, everything else is still the same.