These shows are much like any petro show held in an enclosed location. If you sell out, or have sold most of your stuff, you will probably be heading home on Friday night. If you don't have anything else to do, you might hang around to about 12 on Saturday, after that, you are out of here.
This thing about vendors not staying around all day Friday/Saturday has been brought up many times in the past. It happens at CTO, Iowa Gas, you name it.
If you go to a lot of these shows you learn how they are run, not how the promoters wish they were run. Probably 50% of the sale are made out on the parking lot even before the meet starts, another 10-15% as the vendors are setting up even though the meet has not started.
Not to be smart about this, but don't wait till Saturday to expect anything good to be still available.
Author, 1st & 2nd editions of Gas Pump ID book, 3rd edition is now available at www.gaspumpbible.com
Air Meter ID book also available