You know, I'm not sure how long the Fujiwara instructional is, but a long clip of it is available on youtube. It is in Japanese like you said, but if you are an experienced grappler it isn't like the stuff is beyond your understanding or anything.
As far as how "high percentage" it is, or how applicable, well, people have been doing armlocks and neck cranks for a very, very long time. I don't think it is bad to know anything. At the very least just to know that these things are possible and could, potentially, be used against you. Or maybe you'll see something he did and it may really click for you.