if this will be an ongoing thing regarding your play time then i would suggest a JPN server.

i play odd hours and Cactuar is pretty dead @ 3am but its a good dead. there is a small group of us that run stuff. very chill. easy to do hunts. but the PF is practically empty.
a JPN server at 3am your time will be roughly 3pm theirs, which is why i suggested. look for 'the' unofficial Aussie server so you'll have english speakers to play with.