I know when I wanted to book my tour for October I was told 90 days by my TA. BUT people here were saying they were already booking for Thanksgiving! So I called and booked our October tour back in April, I think. I am just at 90 days NOW, and that tour has been booked and paid for forever.
After I called and booked I found in the UG where it said tours are 1 year in advance. I'm pretty sure it's one year, but may vary from tour to tour?