If you can choose a consistent time of day in the early evening, within 2-3 hours or so, you could use enough flash to overpower the ambient light to create a consistent "look" and "feel" to the images. You can blast light onto the building with a couple of 1200s in large octoboxes set up away from the building and tilted upward. Dial your ISO down to 100, your shutter speed at 1/250 (or max shutter speed for your camera model), and then adjust your aperture until the exposure is black. Then turn your strobes on and meter the exposure. Set your aperture according to the reading. Expose the image. If you have light gaps at the base you could add a couple of 500 kickers with a wider grid to hit those spots. Just make sure you meter again after adding them. (I would set the kickers at 1.5-2 stops below your 1200s.)
You're essentially eliminating the impact of ambient light with flash for consistency. That way cloudy or sunny doesnt matter. You're controlling all of the light. You'll still have to adjust your light positioning based on the size, shape, color of the building, but you can create a consistent look this way.