Now that my brother and I are not no longer considering Gramps, what other options are there? Well, one benefit of free software is they often don't mind telling you about the competition. The Gramps wiki has a page conveniently entitled Other genealogy software. ^_^
Looking through the list, the one I'm going to try next is PhpGedView (screenshots). Yeah, yeah, it's PHP, but that's what a lot of web apps used in the old days. ^_^
At least this one explicitly says it works with PostgreSQL, which is important since I don't want to run two database servers. Strangely, PHP developers seem to prefer MySQL almost exclusively, even though database agnostic PHP libraries have existed for ages now. Maybe it's because LAMP sounds cooler than LAPP. ^_^
I didn't have time to install PhpGedView today. I'll report back once I get "a round toit".