I will be hopefully attending gen con la this year. And since i havent played a major vs event in a long time im hoping i qualify thru this type of event on thursday. My questions are these

Single elimination of swiss??
What places get to qualify for the pc?? if no exact number give me an example.

or any other helpfull info is apreciated...

Single Elim, not sure about the rest.

The number that qualify depends on how many players are in the tournament, I think.

top 4 qualify, single elimination

that is correct. also if u get lucky and get a first round bye then u only have 2 win 2 games. they give out alot of byes first round so that the tourney will even out and finish with top 4.

Are there a lot more people at LCQs at GenCon as opposed to LCQs for non game convention sites? At PC: SF I heard there weren't that many people, but since GenCon is a gamer convention I would assume there would be considerably more?

For Gencon Indy, we had a few that were under 32 players. Gencon Socal isn't usually as attended as Indy, but I'm sure there'll be plenty of people trying to qualify, many of them people who just happened to be in town for the convention anyway.