Second, the top of the tripod does not have anything to lock the tripod head in place. Manfrotto uses set-screws and their heads are designed to accept these screws so as to prevent the head from loosening from the tripod base. Gitzo uses their Power Disk with the Safe Lock material and two locking screws. I'm not sure what other manufacturers use. My Induro monopod has one set-screw plus a slip-resistant material. The Slik tripod I had did not have anything except friction of aluminum against aluminum like the Feisol. Anyway. I was not able to tighten the head on the tripod enough to prevent it from loosening while I was panning to the left. Kind of a hassle. I don't think the Feisol center column has any type of head locking feature either. Again, not a deal breaker since Locktite Blue can be used to secure the head. But an engineered approach by Feisol would be a better solution. I would assume this would be a concern if you were often switching heads.
Does the center column addition (which I think you are not using?) have any set screws to lock the head in place? it's difficult to see on the images provided but it seems not to have any?