Yeah the guy in that video is Bill Hartman, really great to listen to.
It's great that you've identified the problem man! Shorten down that rowing ROM coupled with some pec/shoulder mobility work and that shoulder issue should be gone in no time. As far as upper back strength stick to practicing the new form, along with those low trap exercises I mentioned in that other thread and facepull's if you can.
I just saw your Overhead press video in another thread, pretty nice weight your moving man. One thing I did notice is your head/upper back posture. If you walk through a doorway, your head would pass first then followed by torso etc. Tight upper traps and the muscles in the back of the neck/head cause this, as well as weak front neck muscles. Try making a double chin, with your teeth together, and pulling the top of your head gently forward. Does that stretch good?