my comments are aimed at the playing of dance tunes,not songs, it is important to mention that punch can also be added by using chord notes and octaves regardless of direction.
Seperation of notes is also important
it is acomplex issue,to which there is not a simple answer,but is worth discussing.
http://www.soundlantern.com/UpdatedSoundPage.do?ToId=4507
how about this for making an english soumnd like a duet