It actually takes 3 separate 35 foot cords for a sling like the vid. That's a 43-45" sling. Not all need that big like my semi shotgun but the mossberg persuaded needed it cause tube is full length. I'm making a 36" now, about 30 foot x 3 but some left over. I'd say 10 min per 1000 spool. Takes about 3 hrs relaxed knotting. I think a swivel on the wall and work vertical would speed it up. Seems a tangle mess at first but once set the individual cords lay in piles as you work, not bad once you get going.