Out of all of them, I like your original or version 3 the best. As you said, you have that patch of blue sky in the original. Version 3 is more balanced, and your attention is really drawn to the center tree. Either is pretty powerful in its on way, sort of have the rule of 3's working for you in this image.
to get a really clean rule of thirds...I have to set the horizon on the 3rd line, and I lose too much of the foreground...for me.