When I was 12 I saved up a bout two or three months allowance and bought a Cody Glass Woodsman. It didn't even occur to me to only condition part of the call surface. I took the stone and conditioned all of the glass. It never bothered me, you could still see the inside of the call. I've noticed the call runs better (sounding to me) on certain areas of the call, but it's nice to be able to use the entire circumference of the pot for different tones.