A kit, or family, of interchangeable headlamp parts for a headlight system is provided that enables illuminated light spots of different sizes and/or different light distribution styles to be produced. The headlight system includes a headband, a headlamp mounted on the headband, a light source, and a fiber optic cable having one end connected to the light source and an opposite end tip connected to the headlamp. According to one embodiment, an upper assembly of the headlamp includes a cable mounting module that is moveable relative to a core module and that permits the distance between the end tip of the fiber optic cable and a convergent lens to be adjusted to permit spots with different light distributions to be produced. A method of adjusting the light projected by a headlight system is also provided.