Set the piston at 2.25mm BTDC and then line up the bigger line that furthest from most clockwise with the line on the rotor. Carefully torque the nut so it doesn’t slip, then check it with the light. I have had them where they want to run backward and I have to use the opposite rotational direction marks to time it properly, but that is like 2-3 times out of about 50 installations.