I bought my tickets yesterday and they said no dates were sold out at that point. They can't tell how many are close, they just know there are available for all dates.
I had heard that October 7th was sold out already and I was surprised and sort of bummed out because our plan was to go to that one if we decided we wanted to do a second one. I might not have even thought to check when we were there.
Thanks for the info, off to make sure I have it in my notes to buy tickets on the 3rd for the 7th if we decide to do it twice.