Robert Comsol wrote:
However, the greater the distance from the viewer / camera the distortion effect becomes increasingly less, enabling a comparison of two objects close to one another.
The same applies for the stern view shot, now in color, taken from my European TMP Promotion Portfolio:
So while a ruler or a computer can be a powerful ally to make the necessary dorsal width calculations, it does not replace this kind of experience.
Since you're still fixated on using photos to make your measurements, then consider reading up on distance, perspective, field of view and focal length. None of the photos and screenshots available flatten the features of the ship because they're simply shot too close.
Just from both photo and 3D experience I can tell you that your visual estimates do not replace a good orthographic view of one such as the CG TMP DE version done by FI.