Hi there.
I found a DW specialist/travel agent and we actually booked our trip 1.5 - 2 YEARS in advance. Well, we met with her to figure out what we wanted, etc. She was able to give us prices, etc. We knew it was tentative, due to hotels. But, we got REALLY goood prices. We are flying right before the peak season...end of Nov. I figure, the sooner you look, the sooner you can give people a heads up on your wedding. We wanted to give advance notice, so people could save up and come with us.
Hope that helps.