I would guess the effect would be negligable and impossible to reproduce and related only to the mass the material adds to the instrument. I suspect...
I always expect to be impressed with Gail's work, and, once again, she doesn't disappoint. So glad to have her post again. You're going to love that...
If you're old enough, you'll smile at this... if not, it's a cheesy commercial with a song that sums up your feelings and ones we've all had tracking...