I'd say closer to 100.
As a B player, about 4.5 nowadaze, with a big lefty serve, unusual quickness, and strong 2hbh, I went multiple rounds in 2 different Q's for the pro tourney in SanFrancisco in back to back years.
You just gotta get lucky with the draw, get lucky with one sick player, play one good match, and you're in the finals to make the main. TWICE this happenned to me.
But that 4.5 player had better have a real serve, or at least a couple of real weapons that match up well with 6.0's.