Hi Henri...
Thats so easy to make !! having the exact measures ,and fotos for the wiring.I made it many times .
Having the perfect 90° , 1/2 inch MDF cutted , can do the corners and the upper half moon hole with hand held tools.
MDF is very easy to work material .
I have for sale the lamp holders , red dome , and all the metal parts , if you decide to make it.
Thanks !