Hey, guys, I just woke up from my nap. In spite of the expected response, I stand by my earlier thinking. My reference to racing was not that some folks weren't willing to use a stock Model A suspension configuration, but that those given the option, most did not! The need for a 'shoe' should validate one viewpoint.
Think for a few moments before you install a panhard rod at either end of the chassis that is not the same swing arm length and location as the distance between the outer pivot points of the spring shackles. You might not notice it on dirt, but it will prove to be an expensive encounter on the street/asphalt.
All of this 'technical chassis stuff' is like pissing upwind unless you have a rigid platform from which to monitor suspension movement, balance and predictability. Who is going to be the first one to suggest that a Model A frame has any degree of rigidity? Just as a reference, oval track cars in the early 2,000's had between 7,500 ft./lbs. and 11,400 ft./lbs. per degree. At one point in my restoration endeavors, I 'twisted' ONE Model A frame and it twisted less than 105 ft.lbs. per degree, at which point I forever quit trying to make any suggestions on how to make a Model A handle any better.
Once again, this is only the perceptions of one old man!