I just noticed that the rest of November is open including Thanksgiving (it was not open yet yesterday and this morning).
For those trying to book on IPad or Iphone - if you cannot change the number of people form 2, you may want to try to book it from the main page. I am able to book it by getting to the main dining reservation page, plugging in my dates, 9 PM time and number of people. I do not narrow the search (although you probably could narrow it to just dining event). Then I hit search, and once all restaurants and events pop in, I scroll to Tomorrowland Party and choose the time. I can also at that point choose Tomorrowland Party and get to the calendar page. Number of people will stay the same if I run main search first for that number of people. Then I can check different dates for desired number of people.
We went to the party November last year - I booked it right after November opened. We had a seat at the railig but all the way towards the right. It was not the best place, and people were standing in front of us anyway. so it does not really mater where you sit as long as you able to get it.
Good luck everyone!