Scott,
I just entered "furling" in the search box and got 38 pages with 30 posts per page as results of the search. A lot of reading ;-)
I doubt you'll find a simple answer, as all mills are built differently enough as to need the furling system to be customized to the mill. Furling is to me a little complicated. You need to calculate the blade diameter, the amount of offset between the center of the generator head and the pivot point at the top of the tower, the wind speed you want it to start furling at, ect... Then the size and weight of the tail can be calculated. I remember in the past there was a lot of trial and error involved in getting some mills to furl properly.
Good luck,
Gordy