Great question! The length of webbing needed really depends on the diameter of the object you are building your anchor on. Our rescue team carries webbing in four different lengths 5 foot, 12 foot, 20 foot, 25 foot. As for manufacturer, personally, I have a preference for Sterling products however there are other reputable manufacturers of rope and webbing that make great products. The webbing used in this video is 1 inch tubular webbing rated at 4000 pounds MBS. I hope that answers your question.
I was formerly in the Tennessee National Guard and now in the TN State Guard. We have search and rescue teams and would love to get more in depth training.