I don't understand. I mentioned large glass bulbs like automotive lights but I said nothing about mirrors.

My Light & Motion Urban 900 LED light has a highly developed, shot peened mirror behind the LED.

The high beam on my Exposure Strada 1200 above has a parabolic mirror on one of the LEDs to focus the light.

It seems like the OP is trying to mimic the appearance of a motor vehicle and that's what I'm talking about. A large glass bulb isn't practical.