Thank you for the suggestion, I had in fact settled on near identical values for Diffuse and Ambient shading.
Changing the Shaded to 0 has not made any change that I have been able to see, on this or other tracks I have tried the change value on.
To give another illustration of the problem, the below image shows the concrete spectator seating at night, where the vertical surfaces are being illuminated by the ambient light from the Kyalami pits facing it. So the vertical stand surfaces are being illuminated correctly, but not the camera_facing billboards.
Whilst radically increasing the Ambient value would lighten the overly dark crowds in this lighting condition, it would then also require massive adjustment to the Diffuse value to compensate in normal lighting conditions. In fact, when I tried i was not able to reach a Ambient value that would generate reasonably light crowds in this situation, where Diffuse value was already at zero to compensate.
So what we really need is a way to change how camera_facing billboards are lit, so that as illumination from the front increases the crowds get lighter, like their surroundings, and not darker, as they do now.
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