BOKABA; THE 30 DEGREE ANGLE IS A GOOD STARTING POINT, HOWEVER YOU MUST FIND WHAT'S GOOD FOR YOU.
USE IT IT AS A STARTING POINT AND THEN ADJUST A COUPLE OF DEGREES AND TAKE A MENTAL NOTE OF IT, NEXT TIME CHANGE ANGLE IN SAME DIRECTION AND AGAIN MAKE A MENTAL NOTE. IN OTHER WORDS DON'T JUST RANDOMLY CHANGE THE ANGLES, MAKE IT CALCULATED CHANGES SO YOU CAN FIND WHAT IS CORRECT FOR YOU AT THE DIFFERENT AREAS OF YOUR FACE.