Tom,

 

Consider this.  The relationship between the horizontal and vertical stab on the 300 series is very rigid.  That is, if you move the tip of the horiz up and down, the vertical willdutifully follow suit left and right.  The issue you reference is really related to deflections of the tail cone ahead of the bulk head that goes up the leading edge of the vertical.  Such deflections more likely occur in twist rather than vertically.  The reason for this is that the strong oval shape of the tail cone is incomplete once the vertical stab starts to rise up out of the cone.  Note that the two halves of the vertical stab are only held by 2 bid on the outside of the seam in this area (one cannot get to the inside if one is over 4 years old). 

 

For racing Legacy's, Lancair wraps carbon glass around that part of the tail cone and up the vertical stab. 

 

Another solution to add some rigidity to the 300 series tail is to flox stiff foam into the fuselage from where is starts the vertical stab rise back to the bulk head, shape the foam to follow the interior oval form and apply bids of glass or carbon over the foam and well onto the fuselage to keep the strength of the oval shape. 

 

Scott Krueger

 

PS Mark Ravinsky came up with this in light of longitudinal cracks in the area that rises up from the fuselage.  I added this to my airplane even though I did not perform aerobatics like Mark.  Several others may have done this also.