Title pretty much says it all, I live on the west coast NA (PST, UTC -8:00, pacific time whatever you want to call it) but I work nights so I usually play around 11pm through 4-5am my time, the server my main character on is kind of lonely at this time and while I can deal with dutyfinder playing with FC members or friends would be alot more enjoyable.
I'd like to say Malboro but it seems to be mostly US East and starts getting pretty quiet by 23:00 PST. Have you considered the EU servers?
Ultros ...I just paid the $18 to move my main character there for the same reason. Regardless of the time of day ultros seems to have a decent amount and of people on.
I generally play between 6pm PST until early morning or at least midnight.
Late hours like that on the NA west coast matches up with peak hours in Austrailia. (11 pm to 5 am PST = 5 pm to 11 pm in Sydney.)
I've read that Masamune (JP Legacy); Tonberry (JP New); Sargatanas (NA Legacy) and Behemoth (NA New) are (or at least were at one point) drawing the most Oceanic players. So you might consider one of those, perhaps Behemoth since a NA server will be closer for connectivity purposes and it's harder to start off new on legacy servers. (Of course, those "new" servers aren't really new anymore. They're just ones that started with FFXIV:ARR rather than FFXIV 1.0.)