I'd like to share a strategy I used to master SLS/PE2, as the twisting squats were giving me trouble for a while. (This is also a chance to announce that I finally mastered this PE!)
The problem I was having was I could get through the 5 sets, but had to take little breaks to shake my legs out because I was getting a huge pump in my spinal erectors and my legs. This was making it difficult for me to keep my balance during the twist, as it takes a certain measure of constant tension to keep the twist, and my endurance wasn't quite up to par. This lasted for at least two cycles. So I decided to try something different. I started doing 5 sets of 12 Cossack squats, with 12 twisting squats after each work set, for every SLS workout. I did this for one cycle, and at the end of the cycle, I dropped down to mastery level and was able to master it.
I also changed the surface I was twisting on, which helped me get a smoother twist, and this definitely helped. But I think the main thing was the strategy I used! So I thought I would share this in hopes that it could help someone bust through a plateau. And if it doesn't help anyone, at least I got to make a thread about it because I'm wicked excited about achieving mastery lol.