A "fuse" is a "fuse." It's designed to blow/ burn up, at a predetermined current rating. As such, the length of the "fuse", if changed, will no longer be the same "fuse." You can not use the same gauge wire at different lengths and call it the same fuse. You can test various fuses, all different in length until you find one that burns, consistently, at the same current, but if you change the length at all, you must test it again. Since 90% of the builds I e seen here are all over fused, I'd be very careful when replicating any of these designs.
At first Joes video was just good. He tested some wires and showed the results. Then he made it great by telling everyone to DO THEIR OWN TESTS! That's the point you should take from his experiments.
If you are using a wire that burns at 6A, with a 2000 mAh cell, a laptop cell at that, one rated for 1-1.5C max, per the data sheet, you are letting it pull 3C with a 6A fuse! They do make high drain 18650 which can be used a 3C, hell some up to 6C, but these laptop cells are not designed that way. The good thing is, and the reason no one has had a serious problem yet, is because they haven't actually pushed the cells that hard in their system...the packs have been build so that no single cell has to cure t that much current, which is good, but then why fuse them for it?
Before you are quick to reply, take out a paper and pencil and do the math yourself...then think about it...and you'll have no choice but to say, damn that assholes right...