... not being Brad, I'll offer my own opinion.

I do have a similar set up to Brad's, but my technique is somewhat different, though not regarding weight used to maintain tension.

For the sixteen years that I have been furling leaders, almost exclusively with fly tying thread ( Danville 200 denier Flymaster Plus ), and occasionally 2# fluoro, the weight used for maintaining tension has been a box end wrench attached to medium duty stretch cord. The combination of weight and stretch cord consistently produces excellent tension on my system as I reduce the starting 84" length by about 20% to end up with a 68" leader. That is more reduction than many, if not most, furlers go for, but it produces an excellent leader.

Hope this helps.