more pictures (building) improvement

The image above is the result of a couple of days of fiddling with the settings on the scene, right now I am rendering a new one with some changes.

:: above image, some of the settings I adjusted are; the power of the physical sky multiplier which, due to the kobayashi pluggin, is connected via an expression to the multiplier of the physical sun. I am using the architectural shaders for almost all of the surfaces in the scene; I adjusted the ray multiplier of the concrete which is on the ceiling and the floor, as well as much adjustment on the windows: the reflectivity, the reflectivity color, the cutout opacity but so far have avoided using my own settings for BDRF. I have repeatedly adjusted the spots to get them where I want them, they should be very week in comparison to the sun I think. All and all this experience is crying for more reading on the subject.::

• The biggest hurdle seems to be to get the windows on the left to look like the windows on the right. They are at different angles so the reflectivity is different. It looks to me like the windows on the right aren't even there.
  
• The color of the exterior environment is off, it should be blue sky and brown ground.... not sure what to do there, because the sky/sun is set very low.
• The "cans" in the ceiling are not lit by the spot which sit inside them

The image to the left is the most recent render, the cans are slightly brighter and the spots are more diffuse.