The span of the horizontal stabiliser was increased; the vertical stabiliser was made both taller and wider, to give the required steering power while keeping the top of the vertical fin at a height comfortable for the assembly of the horizontal empennage.
The span of the horizontal stabiliser was increased; the vertical stabiliser was made both taller and deeper by extending the tail boom. In this way the top of the vertical fin was kept at a comfortable height for the assembly of the horizontal empennage.