If we 4:3 Backglass users want to maintain the 16:9 ratio of PuP Backglasses, we always have the problem, that there is some unused space below them. The Fillers are for those (few, I guess). Just use them in one of the screens via PuP Pack Editor. I use Topper, because I don’t have one and this one works flawlessly for me.

And: This radio device is from 1954, so sorry, MONO only.