Thanks John. I have been furling leaders for a dozen or more years. Mostly mono and nylon thread. I have used mono chord (#3?) for dry fly leaders.
I am trying to find a material that will furl tighter. A friend has furled leaders that he has bought that don't look like any that I have ever seen in real time
or on the internet. Heavy butt section and the points at which it tapers are almost invisible. They are super tight. The ones he uses are 4.5 to 5 ft. in length. Can't remember right now where he gets them but I will find out. He has developed a system of nymphing with them and an indicator that has proven extremely effective. Can't give you the exact setup because I haven't weasled it out of him yet...but I'm still trying. I know that a floating leader for nymphing doesn't sound right but it is. I am heading to Northern Ont. this week but I will try to find the video you mentioned soon.
The braid that I have is made of Japanese UHMPE fibres - ultra high modulus polyethylene fibres extremely strong with very little to no stretch.

Thanks again