Well, that was more effort than I expected.
At first, it seemed to go well. The installation went very smoothly and very quickly, and I had a multi site WordPress using subdomains up and running in no time.
Then I tried to use it.
The first problem was when I tried to write a post, and discovered that the text colour was set to white text on a white background. Some googling and some poking around with the Safari debugger showed me how to fix that by hacking the editor.min.css file.
The next problem was trying to change the header image. When I uploaded a file it went to one directory. When I tried to use a file it looked in a different directory. So uploading an image “worked”, but I wasn’t able to use it.
I finally fixed that problem with a lot of experimentation and some clever symbolic links.
It seems to be working now (so far at least). But dammit – I thought WordPress was solid, reliable, tried-and-tested software? Why does it seem so buggy? And how on earth do non-programmer who don’t know how to hack css and create symbolic links manage to use it?