I think repechage's point - and I agree - is that everything on the Waterford drawing (most significantly HTA and STA) except the top tube slope match the angles and dimensions I measured when a baseline through the front and rear dropout centers are used as the datum which is parallel to the ground if the front and rear wheels/tires have the same radius. I have accurately measured the Waterford's fork rake at 42mm and the Campy headset stack height is part of the design. With an HTA of 73° and 700c x 23 wheels, the trail is 59.1mm. If I assume the top tube is level (parallel to the baseline through the dropouts and the ground) and use the top tube as a reference to measure the HTA and STA, the HTA becomes 73.7° and the trail becomes 54.8mm. That gives us a trail 4.3mm shorter than it actually is. Admittedly, a 4.3mm difference in trail may not be detectable by many of us, but it is significant. With the 1973 Super Sport having a 1.0° top tube slope it becomes even more significant.

I'm honestly trying not to be pedantic here.