I like #1 and #4 the most Tony, nice work mate.
I'd recommend giving your sensor a blast of air using a rocket blower (
not compressed air ), as you can see some sensor dust on these.
Also you may want to invest in a filter for your lens if you haven't already to protect the front element.
I highly recommend the
Hoya Super HMC Pro1 UV filter, I always have one on mine.
Some people don't like them because it adds extra glass in the light path but I find they are worth it for piece of mind.
Another filter to keep in mind, especially for this type of imaging, is a
Circular Polarising (PL-CIR) filter.
Make sure it's the circular not the linear PL filter.
