They usually only suggest the "Recommended" realms because they're in need of more people [ie shitty progression/ghost town]. But as you know you can obviously choose any server you wish. Are the hours that you play at going to be permanent or are they subject to change in the near future? You can always choose an Oceanic realm. Contrary to popular belief all Oceanic realms are located in the LA data center and not in the middle of the Pacific ocean.

I would say that any server you choose in the Bloodlust battlegroup is going to be awake at almost all hours of the night. Bloodlust consists of 8 PST, 2 CST, and 9 Oceanic timezone realms as can be seen here. With the diversity of timezones this is by far the most active battlegroup. It is also the battlegroup that seems to have the most issues though...I would guess this is either because of older hardware or the cluster having so many realms with a high population is stressing the servers and things break.

With the hours you're allocating for playtime, any US server you choose that doesn't have a high population is going to end up being a ghost town. Normal people are asleep at that time. I also haven't seen a queue to get into a realm for quite some time. If you chose an Oceanic server but then in the future had to switch your playing time then you'd be in the same 'ghost town' scenario. Only you can decide what's best for your situation. Someone will say their battlegroup is the best they've seen and another person on a different realm in the same battlegroup will say it's the worst. I am currently on Kil'jaeden in the Bloodlust battlegroup where [I'm guessing] the largest Alliance multiboxing guild currently resides. Take your pick of servers...you've got about 240 to choose from.