Setup:

The Main camera's orbit and dolly values where all set to 0 and the script started. If you haven't used the script, it works by measuring the distance between the pointed ends of a couple of props built by the script. The props can be moved around and the distance between them is displayed in a TKInter panel. The Pointer2 prop was moved 1.1 PNU along Z, that's the distance from the front of the Main camera to the origin, and then parented to the camera. The Main camera was set to point at Pointer1 located at the origin of the ground plane. The attached image shows what this looks like using the Aux camera. Pointer1 is hidden in the image but is located at the base of the red '4'. The first test is in the next message.