This is at 81%, felt friggn heavy today which I attribute to stress from finals being over the last couple weeks. Been playing with a wider stance (which I know you can't see from the video), that has proved to feel much more stable. I am noticing that it looks like I do tend to keep the bar over mid foot, hence heels coming up, wondering if that is from how I rack it? Let me know what you think
Try to bring your elbows straight down instead of back and think about pinching the tops of your shoulder blades together. Pulling them back may be causing you to lean forward, in turn, causing your weight to shift forward slightly.
Agree with Blake on the elbows. Get them directly under the bar as much as possible.
Try controlling your descent for a 3 count to see if that helps with your weight shifting. Again, I think this is fairly minor like your front squat. You are literally ass to ankles on these squats, so I don't see any glaring mobility issues.
Before I get under the bar I put my pinkies on the rings so I know I'm centered. Then right before I take the bar off of the rack I scoot them in just outside shoulder width. But it's usually a matter of what's the most comfortable for the lifter.