Easy mounting of these holders so they do not get oblique.
On the inside of the mounting cup there are 2 holes in the sides and corresponding pins in the lens. On the underside of the cup there are 2 sticks that also form the molding of the cup. If you leave these sticks left you drill 2 holes so these sticks fit in the holes. Then you get all the lights straight.
Best results with transparent glass is paint first with clearcoat to get a nice transparent look. To get a realistic look with orange and red color use Tamiya X-26 Orange and Tamiya X-27 Red or similar paints.