Thanks. I've tried a few #nostr relays now.
#strfry seems to be good for local relays, is easy to set up, and doesn't require a database. Easy to back up.
https://github.com/hoytech/strfry
#nostr-rs-relay is also easy to set up, has a nice configuration file, and uses an SQLite database. Also easy to back up.
https://sr.ht/~gheartsfield/nostr-rs-relay/
#wot-relay seems interesting to me. I'll try it out soon :)