As more fs servers open up transfers should be working100% instant and free. If any time you lock a server you should also provide instant transfer off said server to new ones, And ppl can decide to move to smaller server to be with friends. After x days disable it.
Right now it’s a case of convincing x in game friends vs x out of game friends to abandon their current efforts / name / et.c to restart on x server for everyone. It’s a pita and not many would do it. So you have this dilemma