Tig (and John)
I have been furling leaders for 15 years since I met Kathy Scott a a fly fishing convention. Since then, I have been looking for the perfect material for furling. I tried braid line but it is bulky and tends to loosen. I now use Berkley's Nanofil (2-8 lb)for my leaders. Its not a braid but made of "Dyneema" fibers. It has a very thin diameter but has no stretch. The line has very little mass to aid in turnover. I have found that building a 5 ft leader using Kathy Scott's method works great with the NanofiI but modifications are needed from the Kathy Scott method. First I use 15% - 20% reduction. I let furled legs wrapped around each other but l not let the wrapped 2 legs unwind. I keep the leader tight by spraying the wrapped legs with a polyurathane clear coat while still under tension. I am not an materials engineer, but I think the polyurathane dissolves or rearranges some of the fibers and allows the leader to retain the tension after it dries. The tension is very important because it provides the resistance for turning over the fly. Adding 2-5ft of your favorite tippet material provides enough suppleness for dry flies. The good qualities of a Nanofil leader is 1) it floats 2) it last forever 3) it has great turn-over 4) super strong 5) not weakened by wind knots. The down side is that Nanofil runs $20 for 150 yards. I .use the leader for nymphing, dies, and streamers. I make leaders from 1wt to 10 wt. by modifying the # of wraps and the diameter of the line (2lb-8lb). I doubt this is how Tig's friend's leader is made since I have never seen a commercial leader made this way but it sounds like something similar. Good luck in your leader journey. I ended my leader journey 5 years ago.