I have a good friend with a pull type fish weighing scale that goes to a 110 lbs. that I borrowed to set the furling on the PMG mill I built. As soon as I can borrow it again I will test to see how many pounds it takes to begin to lift the tail. If it is too heavy I figure I can trim down the tail or hole saw some holes in it to loose weight.

I used a figure of 99 lbs. of force against a 10' rotor at 15 mph. wind  to set the balance point on the PMG mill which was a direct blade furl design. It worked out real well. Does that figure sound about right for a furling tail design?