Found a posting of Louis's on a different thread that goes to the heart of what we're discussing here. For the life of me I'm drawing a blank on which thread it was, but it was an older one in which he had translated from Yang Zhenji's book.
Here is how he translated one of YZJ's passages:
"Front-Empty Rear-Solid Stances: This kind of stance method is divided into left and right empty stances. The way of doing the left empty stance is that the right foot plants solidly, the left foot lifts upward toward the left front direction, extending out a half-step, using the ball of the foot to touch (dian) the ground, as in the stance of the White Crane Displays Wings posture, [or] by using the heel of the foot to touch the ground, as in the Fist Under Elbow posture. The left and right feet change positions when forming right empty stances. This kind of stance method requires that the rear foot sit solidly. The front foot is not entirely empty; it also possesses some sustaining force (zhicheng de liliang). In the left and right empty stances of Yang Style taijiquan, the front foot is never entirely empty (kong: void, hollow), but must always share responsibility for the weight of the body. The solid foot's share of the weight is a bit more, the empty foot's share of the weight is a bit less. The 'more' and 'less' depend upon the height of the frame, and take the upright alignment of one's weilu (coccyx) and the naturalness of one's turning movements as the measure of appropriateness.
In the stance methods of Yang Style taijiquan, there is no formulation of the kind where 'the solid foot's share of the body's weight is seventy percent, the empty foot's share is thirty percent'.
There is still another kind of front-empty rear-solid stance in which the rear foot is solid, and in which the entire sole of the front empty foot contacts (zhuo) the ground, for instance, Step Back Dispatch Monkey."
This fascinated me, as until I started studying YCF style TCC I had never heard of it. So, being the inquisitive kind of guy I am, I copied and pasted this into an e-mail (hope you don't mind Louis) and sent it to my Wu disciple friends.
Here is what one Wu disciple had to say on the subject:
"Never heard of using the yin leg for balance. You should always be weighted on one leg, except in transition when moving from one leg to the other. That is a given during the form, with very, very few instances when you are completely double weighted. You should not rely on the empty, yin, leg, it should be completely empty with no weight or support for your body in it at all. This allows you the freedom to move or step in any direction at any time."
Talk about a difference in theory! At least they confirmed for me, again, that I am not delusional in my rememberance of Wu family movement theory.
It does, however, point out what appears to be a profound difference of opinion between these two family styles.
I wonder how the styles got seperated so completely in such a short amount of time?
Now, YZJ DOES make reference to "frame" in his quote, which bears out, to some small extent, my personal theory that "frame" is very important in weight distribution between the styles.
Apparently, in small frame, like the Wu style I studied, a clean 100/0 split is correct while in the larger frames the split will be different depending on what frame you are using.
Nothing really earthshakingly new here, but at least some confirmation for me in my pet theory.
I think we all knew that, but I also know that it does need to be said as I have done so myself, many times.