Sounds like you have a great system working for you. I will include my full mix for future downloads, meanwhile you can take the “audio only” from any Youtube video and make it work on your software as you described.
Go to this website and you’ll see a space which allows you to copy in any youtube url and in about 2 seconds you can download the video’s audio to your desktop as an mp3: http://www.youtube-mp3.org/
also, if you use the program VLC media player (its a free download that will play any media file), you can slow the track down as johnny has them without converting them. Just go into the playback menu and there are different speeds to slow. Good luck.