from what I'm hearing from everyone.. the fast bikes will be out there on the 23rd. So if your looking to do some racing to go along with the dune riding.. or just want to see some fast bikes run. the 23rd would be a better choice. As of right now I know of about 15 people making it on the weekend of the 23rd
I usually setup the HQ ride on the 3rd weekend after the 4th of July to give people time to rebuild their bikes and bank accounts from the holiday.