David, I have this feeling that if you take the raw that came from your camera, adjust to make sure there's a bit of white clipping and a bit of black clipping, do a reasonable bit of sharpening, and quit screwing around with it, you'll have the best possible result. Everyone seems to get carried away with post-processing, but the processing that really matters is what takes place at the moment you trip the shutter. There's always a possibility that you'll need to make a small white balance adjustment, but in this picture that's a piece of cake. You have some heavy clouds in the picture. Heavy clouds are gray. A single click on the underside of a dark cloud with the middle gray dropper in ACR should take care of that. Instead of hovering over the computer, go out and shoot some more pictures. You're doing great.