P.S. The parts and material costs of our windvane my seem low compared to a Free-Hand Unit but I did not add my labor. Researching, designing, sourcing, purchasing and manufacturing the unit required a tremendous amount of time. In addition, there is the development testing of the unit. Balancing the trim tab required three design modidfications to the tab. Based on my experience, I can well understand why the Free-Hand units cost so much.
Esthetically, the Pardey style windvane self-steering system fits the BCC and it does work. Further, oceans have been crossed with these units - "the proof is in the pudding."