Classes will not require you to rechoose, instead, you spawn the first time as a random class, when alive (or dead, meh) you can type "/chooseclass <class>" like normal, but it won't change you, it'll simply set the class you'll spawn as next time.
Also, as soon as Kalphiter sets up his server, the server will go up, forever, completely dedicated, hopefully not going down for days-weeks at a time, and without lag, and a 99 max player count. (or just 32, it's not like it matters)