A "space" is roughly the size of a pickup truck with trailer behind. We don't use the square feet method. The fee is for the whole weekend. Vendors start lining up several days in advance in the parking lot. The gates open on Thurs afternoon about 5pm and let in as many as possible till dark, then the rest are let in on Fri. morning at 6am. Hope this helps.
Be sure to click on the swap meet button on the top of the home page and then go to the rules page for more info.