Just a little heads up – the two point grid is for a very short lens and the matte painting will look squeezed because the two vanishing points are very close to each other.
If you need a longer lens look then use the one point grid and duplicate it as a second layer set to multiply in photoshop. this way you can adjust the convergance for the the type of lens you are aiming for.
General rule – long lens vanishing points wide apart, short lens vanishing points closer. Normal lens 50-80mm 35mm 90 degress from the camera position.