Hi Ed, you were given an expensive present. I know the guys in Flagstaff AZ have been working continuously on improving design and fabrication of the blades. A helicopter pilot taught me how to minimize noise: keep the blades clean, especially the leading edge and grind or sand off the leading edge till it's a smooth round which cuts the air more friendly. My generation of blades was sold out the mold just like that without any further work, just tuning their positions by drilling the mounting holes and grinding the mounting stud. Dunno how they are now, but they must be better. Perhaps you can make a temporary setup (under current load!) to see if you like it.
Michel Capel, Freedom 44 #4 1981 'Alabama Queen', NED8188, cat ketch with wishbones, home port Enkhuizen, the Netherlands, 52*42.238'N 005*18.154'E.