If you can't get a motorcycle visor, you might try using a clear welding face shield with gold reflective window tint film. Try auto parts stores for the window tint film, you may have to buy it online though, as it's not a common item. Be careful if you need to re-shape the visor with a heat gun, some chromed finishes will crack, peel, or discolor. It is safer just to fill in any gaps between the visor and helmet. You can either bondo the gap or use weather strip type foam as a gasket around the visor (looks better on some helmets than others).
