Discovery during yilu practice

In the last few days, I am starting to feel a more solid fixed point at the kua. It seems to be important to keep that point fixed when moving other parts of the body, e.g. for touch blocking coat, while the right elbow-in of the positive circle, the left elbow-in of the negative circle, and the shovel-out of the right heel with a striaght knee all happen at the same time, the left kua needs to be fixed, and that seems to be made possible by creating a stick between the left kua and the left heel.  This discovery seems to be related the lower stance, which allows the frame of the body to be more rigid. Since the frame is more fixed, I can try to move the "inside" more. The lower stance at first seems to cause more muscle tension, as my body tries to keep it together by tightening the muscles. That has made yilu practice much more tiring. The same thing still happens with the first few yilus each day. However, after those several yilus, I am starting to experience that I can let the structure (bones) to take the load (weight of the body), and the fixed point at the kua becomes more apparent.