I think this is highly variable. The best is to have a 3D CT scan done. This probably will cost about $200-400? Facialteam does one for free at the consultations, but I guess you can also make one elsewhere and have the advantage to show it to all the surgeons you like. A good FFS surgeon should always ask for one or do one at the clinic anyways to plan the surgery, otherwise he is sort of starting the surgery without a plan on what is going to be in there - this is important for sinus cavity as well as position of some nerves of the eyes and lip/chin/jaw