Hi Gene and David,
Gene, I read the story you quote from and found it intriguing; however, I am not sure that what Zhang says is readily translatable to Yang Style. I frankly also wonder if this is a standard view of Chen Style since it differs in several respects from what I had been led to understand about Chen Style.
The classics referenced by the Yangs do refer to the same grievous errors described by Zhang, but they are described only as the opposites of sticking, adhering, connecting, and following (zhan, nian, lian, sui). I do not recall that the rest of Zhang's ideas are described anywhere.
My understanding of Yang Style is that the type of Peng energy apparently referred to by Zhang is prominent and to some degree always present in Yang Style movements. I also have not heard of peng, spiral motion, body turning, and sinking the kua (?) as being a group of four alternating energies.