The plane angle used here is clubshaft, which in turn will create a much larger arc on the ground than LEFT SHOULDER.
Straight back and through is fine as long as the thorasic region of the spine is horizontal to the ground. By doing this you will use a dual vertical hinge.
If the spine is angled to the ground an angle hinge will be produced.
Trace the straight plane line and figure out where the movement is coming from. Is it the right shoulder, is it the right elbow, is it the wrists, etc. Mixing is dangerous because too many compensating movements are going on at once.