saddle placement in general
I haven't watched the video yet but let me answer you question regarding the placement of saddles. I looked at your photo and it may be a bit too far forward, the photo is kind of dark so that it's hard to see where that horse's shoulder blade and its' back edge really are. In any case, in a Western saddle, the conch (which marks the front edge of the tree) should be just about an inch behind the back edge of the shoulder blade of the horse when it is standing square. The western saddles's skirt will extend actually over the shoulder area, and as such it must be loose enough (have enough "flare" outward from the body of the horse) so that the shoulder blade can move back and forth to a small degree UNDER the skirt. If the saddle is too tightly fitted at the shoulder it will disallow this freedom of movement. Or if it is too far forward the tree itself , where the actual weight of the rider is carried, will be on top of the shoulder and pinching it.
Does this make sense? Looking at that photo, I am wondering if that saddle isn't lacking in the kind of freedom for the shoulderblade that I talked about with "flare" in the front edge.
Or, it is a bit too far forward.
Now, to watch that video and if you can stand my yakking, I will make another post. . . .