David;
I have a jig that makes a bit simpler leader but had the same problem. The spinning (furling) process takes longer than laying up the leader as it takes quite a while for the weight to come to a stop!
I have several cup hooks in a ceiling beam and hang the leaders from them to furl while I lay up and twist another one. I'll do 5 or 6 and then sit down and do the Shorb Loops.
What thread are you using?