Got to mention also, I have to take issue with your long line video, no dog should ever be on a long line attached to collar, only ever to a suitable harness.
Any dog on a long line might spook or spot something to head after, whether a usually predictable dog or one just starting out on basics training, hitting the end of a long line at speed with it attached to collar has the potential for causing major and possibly fatal throat, neck and spinal damage, even more so than one straining on a standard lead or being jerked, on any collar type.
The only safe way with a long line is a correctly fitted wide banded harness, [ the wider the better, and padded is even better ], through which speed impact is dissipated evenly to avoid injury and which enables the dog to maintain better balance.
I strongly urge you to re-think the video with this in mind because you know people will try at home what you are showing, that`s why you sell instructional DVDs after all.

I don`t personally feel it`s appropriate nor responsible to sell something as advice which carries serious injury potential