Last test shot, I am now familiar with where to adjust the filter in a variety of light conditions.
Here the sky light was much brighter than the foreground elements, the filter balanced the light very nicely.
Not much wind for this shot, just a slight breeze. I didn't note the low shutter speed in the viewfinder.
Had I done so I would have set the camera for a 3 second delay to let camera shake when triggering the shutter from adding any blur.
That would have made the image somewhat sharper.

Nikon D800, AF-S Nikkor 50mm F/1.4G, Lee filters .6 soft GND, tripod
1/13s f/5.6 at 50.0mm iso100, matrix metering, WB preset via white reference card.