There is clear evidence of some experimenting done on this experimental aircraft over the years, specifically in the horizontal stabilizer area. The plates that secure/locate the leading edges of the horizontal stabilizers had many holes in them: four on the pilot side; six on the passenger side.
We fabbed up some new plates and drilled the holes as close as possible to the holes that were being used on the old plates.
Steve W designed the Tailwind with a small tailplane to reduce the drag.
However this will only work if your CG is close to the aft limits.
Most Tailwinds end up nose heavy, so the tailplane nose has to be set lower in order to be pitch stable
Tailwinds with forward CG and low nose set tailplane have much higher drag
The holes in the old brackets shows that someone was trying to find the sweet spot, pitch stable/CG position