I found a nice way to figure out the keys.
Find a you tube vid of the song.
Open the link with vlc and slow it down.
With the scale finder tool it should then be easy, to pick a right scale.
Of course not all vids are suited for this, but searching in you tube with the name of the song and how to play, works most of the time.
https://www.youtube.com/watch?v=eeaNnE323gU
Edit: Just my luck, it wont work for me with this video.
Edit2: this one works :
https://www.youtube.com/watch?v=kkayxWRx07Q
Find a you tube vid of the song.
Open the link with vlc and slow it down.
With the scale finder tool it should then be easy, to pick a right scale.
Of course not all vids are suited for this, but searching in you tube with the name of the song and how to play, works most of the time.
https://www.youtube.com/watch?v=eeaNnE323gU
Edit: Just my luck, it wont work for me with this video.
Edit2: this one works :
https://www.youtube.com/watch?v=kkayxWRx07Q