The plan to change the design of the 215 is one way to fix the problem - but it takes away an important element of the design - the access to the inside of the rock to hide also known as the cave space - so you cannot do that.Instead, make the following change - change the ornament so the back cut out hole is gone.fill in the back indentation and create the layers to make it match the rest of the piece.then you will only have one hole to cut and you can make sure there are no sharp edges - they can cut it and bevel the cut.