1. I think that some people will offer you NA servers, which makes sense but this year we are finally getting EU situated dataservers and you would miss the great latency improvement plus probably many people from EU will move to EU servers.
2. I would offer you Ragnarok, for one simple reason. It is one of the biggest EU servers, so even at 9am - 5pm you can find many parties. For example I have recently done my weekly farm of Alexander at 3 PM or farmed Levi extreme for glamours at 11 AM. We also have many hunt linkshells here, with some glamour and pvp farm linkshells.

I do not know what is the situation on other servers so I would definitely suggest waiting for answers from other people.