Summertop: The fewer starting points is a false question... the number of rounds (and hence the game length) is determined by the number of starting players not the number of points you start with.
Since one player is eliminated each round you have at most n - 1 rounds (being n the number of players) even if you start with just 30 points.

Come to think of it, a 30 point game with 20 players might be something fun to watch... this would really need some guts to place a bet