I picked up some cob reflectors on eBay 6 for $15. They are 98mm made from aluminum and advertized as narrow beam? U guys probably are already aware of this type tho......instead of dimpled aluminum sheet would a automotive windshield reflector that has all kinds of dimples,easy to cut bend and work with suffice?$3 a piece glued to back material or framework might be easier?............and I have a slip roller to make cones outta metal........