Good and Bad about Blue Ox Sway Pro

BenK wrote:
Progressive....bats arr tappered...therefore progressive as they bend more

Ben, being tapered does not make a bar "progressive".

A WD bar is a simple cantilever beam -- and it has to obey the basic laws of physics.
The equation for deflection of a tapered cantilever is given in Tapered Beam Bending Equation and Calculator.

As you can see, the relationship between deflection and load is linear.
If you increase load, "F", by x%, the deflection, "d", increases by x%.
In order for the beam to be "progressive", the relationship would have to be non-linear.

Different axis of rotation centers of ball vs bars....plus different plans

I don't know the significance of this. Can you elaborate?

Ron