Setting up closeder is not doing anything wrong: it is simply CORRECTLY ALIGNING your natural swing path with the intended target line. I say this because your extremely small outward movement of your right shoulder is almost negligible: so much so that I would NOT want to change you if you feel good swinging. It is OPTICAL -- the change of alignment, not MECHANICAL.
I understand your "fear of embedding wrong motions" but you don't swing wronger than Trevino, Nicklaus, Furyk, or Couples. These men adapted their stance TO THEIR OWN ANATOMY.
Next time you see DLIII on the tee, note how his feet are aligned; WAY CLOSED. He is another who doesn't fight himself: it is just common sense.
If you are determined to keep your right shoulder back, just do indoor easy swing drills with sawed off clubs and watch your down the line movement in a mirror or in video playback, to monitor that you do NOT go out with your shoulder. It is really a very small adjustment compared to what's on that vid...