That's a good question. Behemoth is a well populated server, and I moved here from Diabolos a while back. I created a "feeler" to scope out the MB before I transfered so I could convert my gil to items to make a return/profit since you can only transfer with a mil, retainers with, what 100k i think; but I got the message that the server was full. I was able to work out the items with friends on the server, and when I went through the server transfer, all was well. Popped right in.

To be safe and super sure, I would research the support site and maybe submit a request or online chat. That way you get the verification from the horses mouth.