My friend, just a suggestion, I see a lots of photos are in relatively smaller apertures, probably because you wanted a longer shutter speed. But in the long run you wants stronger ND filters, because relatively small aperture will result in lens diffraction, everything will be in focus but it will be less sharp and less details in full view, you want to find the balance.
I'm fully aware of that, and like you said, it's because I wanted the longest exposure time. Normally I shoot between f/14 and f/16. On this particular shot I used a LEE ND standard + ND hard grad 0.6. Thanks for the concern! =)
This summer I invested in a LEE Big Stopper, and that way I'm able to keep to the sharpest aperture and still get the exposure time I want =)