My reply just on this point :
'secondly also that 30 minutes tweaking per render, are not themselves a good thing'
I've had some information from designers who use DAZ3D, I think it's the same for other 3D tools that allow you to set up a scene. The adjustments, and in particular the light, are capital parameters on the quality of the final rendering.
I don't know if it takes more or less than 30 minutes.
At first I thought sometimes it was wasted time.
Now, with these new elements and the differences that I could see, I am convinced that there is an absolute necessity to spend at least this time to make these adjustments.
I know that there are certain presets, which allow you to do a lot of things. For example, to simulate different times of the day (twilight, dawn, morning, night, ...) , cold or warn atmosphere, etc.
It was just so that we had a better knowledge of the elements to take into account.