First of all, thank you for your responses
Well I can now narrow down the server search a lot more! Tonberry and Behemot do seem like the best bet, since their peak time matches my playtime. I'll have to see about that ping tho. Luckly I could make a character on Behemot yesterday really late at night (no luck on Tonberry), so I'll check it .
If Ragnarok really does have a good activity during those times, then I guess it's also a good bet, but I'm worried If I want to do end content in the future there won't be any FC's raiding at that time.
I'll do a bit of research on those 3 and decide from there

Again, thank you for your time