Since an improvised cardboard-version of this "brightness booster" showed promising results in this project log (with video), I went into setting up a 3D printable version of the brighntess booster in OpenSCAD. This add-on adresses some homogeneity and brighntess issues I experienced on large installations of 3+ Hoverlay II modules. For smaller installations, it will probably not be necessary at all. It's basically a fan duct that snaps onto the inlets of the pressure compensation tube. The pressure compensation tubes are not necessary when using the brightness booster.
You'll need two of them for the left and right end of the installation. Each one requires a standard 60 mm fan and two more of the power connectors (male) plus some cables. The OpenSCAD file is configureable and will adapt to 40, 60 and 80 mm fans just by changing the fan_size variable.
Just add a fan, snap it on and you'll have the brightest Hoverlay you've ever seen.
It's designed for 3D printing on a FFF machine with a minimum of support structures. The base plate, where the long bridges occur, is a bit thicker to even out the sagging in the bridge. You could also use Slic3r's cut plane option and print the base plate seperately.
I've been successfully printing this using a low density support structure with interface layers. You might be also lucky ticking "don't support bridges" in Slic3r. If you run into trouble printing this see my support settings:
I'll add some photos of the printed installed boosters soon.