Nillo, where is the album?
Hoop, I stopped the reflector where I did because if I extend the same curve downward then it starts curling under the light. It might be possible to improve the effect by extending the reflector down a little, but I'm not sure about that.
I don't think a 1/2" flat spot right behind the lamp is a good idea. That would be half the width of the lamp itself and would just reflect a lot of the light back into the tube. The idea is to get that light reflected out from behind the tube. I expect that sheet metal reflectors would be mounted either at the top of the curve in the reflector or at the ends, not directly behind the lamp.