Here's my edit. Let me know what you think.
The sky you selected is a bit too blue, see how different it is than the color cast on the latter? Might look a little more natural if you change the blend mode of your cloud layer from Normal to Overlay. That'll keep the clouds but basically lay it into the same sky that actually exists instead of the wrong blue, so the color temp of the sky will coincide with the lighting on your subject. Also, use the refine tool to clean up the edges of your mask...smart radius & a little tweaking of the feather/contrast will work wonders.