Hi Daniel,
Nice to see you making progress.
A comment on the cable strategy - I've generally found a cable to be a pain if the tower is of any height to speak of. It relies on two things working well: 1) that you have a reliable strain relief to account for the weight of the cable and 2) that the friction of the cable and pulleys does not change due to dirt, lack of lubrication, corrosion, icing, etc. In the case of adding a weight you may encounter one additonal issue. If the furling is set up right, it should take more force to get it to furl than to keep it there. This is accomplised by the moment arm shifting in relation to the yaw axis, and makes sense considering that the rotor thrust drops as it furls. The problem I've encountered is where the cable (and weights in your case) restricts the restoring motion.
I wish I could offer a better solution. We're planning a lighter line and an enclosed linlkage at the machine, but are using it just to manually furl if/when needed. Sounds like Fab' is using neumatics with success. I suppose hydraulic or motor-actuators are an alternative, but add complexity. It is still a design element I'm not totally happy with, with ours.
best of luck,
~kitestrings