The reflector is probably made of a thin reflectiv aluminum. The screws don't need to be any longer than 1/2". As far as the end caps go, the light bulb is what actually holds them in place. There's also probably some bulb clips which screw thru the reflector and into the canopy, thats what actually holds the bulbs in place. If you feel the screws are in sufficient you can always hop in the car and get some longer ones at Home Depot or your local hardware store.