Cady, I like the sphere notion for neutral structure, but from a peng jin standpoint there may be a risk in losing the notion of the Qi of Earth whereby you're mentally manipulating the solidity of the ground through you (initially, then as you get better and more relaxed, you can do more with gravity as well) because in an initial practice, you don't usually have the connectivity to do much ground transmission without relying on bracing or structure.
Not sure what you mean. The sphere is always there, both in neutral structure and when changing and acting. And connection with the Earth is always part of the equation, even when moving and stepping.
It's all about increasing layers of "stuff" we're doing, with the basic structure and holding of the (intent) sphere as the foundation.