Eliza Carthy holds it resting sort of on her collarbone or more in the middle of her sternum, and she plays a lot of double stops. As a singer, I can tell you that you DON'T want to twist your head to the side as you sing. Do yourself a huge favour and leave your head free or you're going to do funny things to your neck & throat muscles. By the way, I doubt you're going to have any problem hearing your fiddle if you hold it a little low. After all, I don't see any guitar players drooping their heads over their instruments full time!