How does the TPLink compare with the 6D's wifi? I was thinking about switching to that system, but I couldn't find many reviews from other 6D users. I would think the range would be closer to 150ft like the camranger given that it's the same hardware?
Make sure to use a sun tracker http://suncalc.net ...-0.125,2/2016.10.13/09:06 to time your shots.
I don't know that you need to wait and wait to get your light right, but planning would certainly help. Think about what you can and can't blend. The ground should be easy to mask in if it's too dark, but doing a lot of blending in the tree/sky area could be problematic because trees move, so things won't line up. It's hard to say for sure, but this photo doesn't look like the sky has been replaced, and it would be a mess with so many tiny gaps in the trees.