And don't forget--you can personalize your flights when you book, or when airlines publish their new schedules. (E.g., GCT couldn't book my flights because the airlines have not published 2013 flights yet for my trips which begin in Sept 2013 and end in Feb 2014--they need 330 days out, as I checked myself). But, I was a lucky person in that they did find me Sept /Oct 2013 flights, and it is an airline that I would have wanted anyway, so I was lucky.
According to their ads, brochures, website, they can personalize your flights for a fee, or if you are inner circle, they mostly waive that fee. So, you can talk with the Air Dept and see what they can do for the flights you want. For my flights, the GCT price was the best price, and the schedule I want, too.