@zeltak - You're Welcome.
As far as your latest question, I have an iMac 27inch so I don't have your particular setup. Don't be afraid to test it out and report back. If it doesn't work, you can easily modify the macro to cover both screens or make one for your 4k screen and another for your laptop.
Search Screen Size, in the forum.
A quick link for you to research and try:
Best way to test for screen size?
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As long as you don't have Keyboard Maestro deleting important files or running scripts that you don't fully understand, it's ok to experiment. In this case, you are the SME (Subject Matter Expert) for your particular circumstance. Try it out! 
KC