Section 2 For Experienced players in Tai Chi.
The observation here is that there are some Seniors with very tight hips, some Seniors with nearly fused lumbar region, and some Seniors with loose hips. There are going to be different limits and maintaining optimal range of motion on hip rotation for different individuals. Much depends on the application or next movement in Tai Chi form, whether for health in exercising and maintaining foot, ankle, and hip range of motion in TCA&FP.
As an anecdote and research, I showed the TCA Tie Coat to my Yang24 teacher and my Shifu in 5-Element Tai Chi. The Yang24 teacher is well versed in Aikido too. These experienced players both interpreted the first part & bottom half of the tray carry in Tie Coat as a strike to the left side and the second part & top half of the tray carry as a push or Two Hand Push. This interpretation may have some validity, as the Two Hand Push in Tai Chi is sometimes preceded by a strike. The application for Tie Coat taught in TCA&FP is a Push or Two Hand Push, in opinion. So maybe, the end application of Tie Coat is in the eye of the beholder and the intention mind Yi of the Tai Chi player?