There are a new things I have noticed:
In Chum Kui, section 1, the lan sau to bong sau is moving in a circular direction. When you move with your mass – and link that mass with your limbs – then you can see the circle clearly
In Chum Kui, section 2, the bong sau needs a slight pivot. Without a slight pivot, the bong isn’t getting energized. Also, it’s moving in 1) a circular motion and 2) a corkscrew motion. It is also moving in a circular arc but reaches its destination in a straight line.
In Chum Kui, section 3, the bong sau is energized by the center mass. Every movement is linked with the center mass. This includes stepping and turning. From sections 3 to 4, this is where I have noticed these requirements.