Donald, The proper design for all models of Coupe is for the window sill to be level when the airplane is sitting on level ground.
With the original nose gear fork the tail should be 75" high. With the double fork nose gear, which is about 1.5" longer, the needed tail height would be 76.5". Back to the basics, the criteria is for the window sills to be level - that's what gives the correct wing angle of attack on the ground, dumping lift and allowing the correct crosswind takeoff and landing safety. You can find the detailed information on tail height and spacers written by Bill Coons on Skyport's website, way down at the bottom of the page: http://ercoupeparts.com Ed Burkhead
