Logitech (or similar) Computer Speaker Holders

I wanted to get my speakers up off my desk to make more space, so I designed these simple boxes to screw them to the upper portion of my desk. I made them to fit my speakers which are Logitech model Z213 found here on Amazon,
https://www.amazon.com/Logitech-Multimedia-Speakers-Mobile-Devices/dp/B00KK9481I/ref=sr_1_1?s=electronics&ie=UTF8&qid=1547390802&sr=1-1&keywords=logitech+z213

The holders have a printed inside dimension of approximately 79.5mm both ways (width and depth). I designed the