Hello everyone,
May i suggest swiching to Discord instead? It is an app that most gamers use these days, it is free for all and with a little bit of knowledge you can create a discord group that can easly be as good as a ts3 server, without any additional cost to the community. From what i can see most servers already have their own discord channels, so their admins can talk easly betwen them without having to go to the community's ts3 server.
My opinion for the moment you can choose a 64 slot server for this month, but if you choose you can relate to the users that you will be swiching to Discord in the near future, in this way you have time to get the announcement to everyone and you won't loose any activity, thank you.