Too lazy to build a jig and too clumsy to twist furled leaders by hand, I used a simple rope making technique to make furled leader section about five feet long, which is about my arm span.
The rope making technique is fairly well described here . However I do a couple of things differently.
First, you need something like a hook on a wall or a bolt and hasp. Cut a piece of monofilament about two and a half to three times longer than you need (suggest three arm spans for starters). Loop the mono over the hook at about the half way point, knot the two ends together (single or double overhand knot is fine). Insert a piece of dowel, or ballpoint pen or pencil or anything similar at the knotted end. Walk backwards and gently stretch the mono.
Take the two strands in your left hand and pinch them close to the pencil. Wind the pencil around and around and around…putting a twist into the two strands. When you get to the point where you feel the mono pulling you towards the hook, stop twisting.
Holding the mono taut with one hand holding the pencil, grab the twisted mono at about the half way point and then take the pencil end to the hook. Hold both ends together and gradually release pressure on the folded part. The mono will now countertwist on itself.
Straighten out any kinks. keep holding the loose ends and remove the mono from the hook. Tie a triple surgeon’s loop in this end and cut off the excess mono. You will now a have a furled leader section with a surgeon’s loop at one end and a doubled-over loop at the other end.
For the leader in the photo, I made three sections (5 feet of 25 pound, 3 feet of 15 pound and two feet of 8 pound mono). These are joined folded loop (upper section) to surgeon’s loop (lower section). A single strand piece of mono (surgeon’s loops at both ends ) is added at the bottom for adding the tippet.