I removed an old nut tonight from an SX neck. I got it out fairly easy. I'm replacing with a tusq nut, but the old slot for the nut seems to be bigger than the new nut. The new nut doesn't seem thick enough, it drops in and wiggles north and south quite a bit. The width is fine though. Is this normal or do I need to fill that slot with something to make it a snug fit?