I dont think you can because they would want people making there amount like 10000000000000000000 or something.
[Blockland Folder]/config/server/prefs.cs$Pref::Server::MaxPlayers = "";This.
But wouldn't I have to open more ports to allow a higher number?
Or, host a Dedicated LAN with a Max of 1337 players so you don't have to port-forward :3