The fascia is made of 5" wide strips of 1/8" tempered hardboard fastened to the front boards with drywall screws and finishing washers. I used vinyl paneling molding between all vertical seams to yield a nice, clean look. When completed, the fascia will be primed and painted to match the color of the room walls.
The following two photos show the dramatic improvement from installing the fascia. The two photos show the helix base taken from basically the same angle, but the first was taken before installation of the fascia and the second was taken afterwards. Notice how much more "pleasant" everything looks with the lights blocked out by the fascia:


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