I AM DOING SHADOW BOX ON MY WALLS WITH 1.5 INCH MOLDING. I AM USING A 10" COMPOUND MITRE SAW. WHEN I DO THE RECTANGULAR BOXES I AM OK WITH THE MITRES. I AM HAVING TROUBLE CUTTING THE MITRES FOR A TRIANGLE PIECE THAT FOLLOWS THE SLOPE UNDER THE STAIRCASE. I AM OK WITH THE 90 DEGREE ANGLE, BUT AM HAVING DIFFICULTY WITH THE 2- 45 DEGREE ANGLES BECAUSE OF THE SLOPE. ANY SUGGESTIONS. THANK YOU