If you can fix your technique and build more strength out of the hole you will fly right past your sticking point. I notice you are doing pause squats too, a lot of people benefit from those but personally I find pin squats are better for me. One isn't necessarily better than another, it's just about what works for you.
I don't really use percentages, I mostly base my training off RPE these days. If you have never done pin squats before then they will probably be a lot harder than you expect. I would do pin squats in the 3-5 rep range, work up to a hard set with 2 reps left in the tank (@8 if you want to use RPE) and repeat 1-3 times. Mike Tuchscherer has some youtube videos of himself doing pin squats, check those out to see the right technique.
Another thing that might help you is squatting against bands. If you're off balance they will make you want to fall over, so your body will learn the right movement pattern fast. Just don't use too much band tension, only about 15-20%.