You will need to angle the headstock back at 13 - 15 degrees. The best way to do this is to cut the neck at the angle you want and then flip the headstock over. Glue the cut piece to the back side of the neck. It's hard to explain, but its not as bad as it sounds. There is a picture below showing the angle of the cut. After the glue is dry you can drill the holes for the tuners. Before you drill these holes, you will need to know the size of the bushings that the tuners use to ensure a tight fit.