oldschool is dead anyway. and tibianic never had 300 players on. classictibia did, because it was owned by a trustworthy hoster who didn't need some pocket money + it was using the identical tibia files, rather then being owned by some greedy polak who closes/re-opens servers whenever he's in the need of money.
you'll only get 50 players online, thats my bet. which will all leave rapidly when the 2x exp sinks in with no quests.