Yes, IPv6-first is definitely the way to do it. Just be careful not to run into Github's issue (https://www.githubstatus.com/incidents/5y8b8lsqbbyq) or Google's issue (https://i.imgur.com/4gGECJ9.png - in case you're not familiar, 2002:: is the 6to4 prefix, and 2002:a0 is the 6to4 version of 10/8, so I guess somehow I was deleting old users from within Google's own network!)