PS - did CPLR move the fin to change the effect, or move it to get it off the removable canopy and better fixed to the plane? Its nice to have the WC stories come out.
As I understand it there were issues with it being fixed to the canopy (I think vibration/flexing and such). If you will notice in various pics BPLR has his mounted to his canopy.
I have played with them myself and dont feel longitudinal position (within reason) has much of an effect.