How well does the head stand up to abuse with the flanges protruding out so far unsupported? If I were building it I would have mounted id so the the jointed section was at the far end and the flanges only protruded an inch or two beyond that. Or just have done all the flanges in the smaller size and every thing else as you did it.
Also have you tested how it does against various materials? I would think that more triangular points would penetrate better, however I would think that even if the flanges were just rectangles of steel it would put quite a nice crease in an old steel pot helmet.