Looks like this is old, I was just interested in the read.
Can you do Pistol squats? Ive known people who can leg press and squat pretty heavy, or at least more than their own body weight, and can not pistol squat. The reason is not strength or flexibility, but balance.
Didnt get a chance to see the video, but here are somethings I did to help me.
Of course, just do it with no weights, or much less to practice form. As far as stance goes, I heard that if you jump in the air a few times then land, that is about where youll want your feet for your squat.
As far as back rounding problems, asian squats are good, but I also did dumbell squats, but holding plates. I would grab two 45s, not sure what to call the hold, but similar to what youd do at the top of a thruster before the pull, and squat all the way down. This made it real easy to squat real deep and because they were plates, it helped me develop balance while keeping good form.
Foam rollers are the best. I had a lot of IT band problems, which was also limiting my depth, and it got em all out.