Shelf for be quiet! Pure Base 500DX PC Case

I habitually place stuff everywhere, including the Top of My PC. The only bad thing about that is that I obstruct the Ariflow of my AIO. That's why I made this Shelf. The Complete dimensions are 230mm wide, 400mm long, and 70mm tall. It's 2 Parts that fit perfectly on the X1C Bed and has 2 Screw Holes for M5 Screws.

It fits fine on a bequiet! Pure Base 500 BX
 
There are 3 Variants as of now. 
One is without honeycombs but with slots, which you can see in my pictures. The slots I added to the model were intended for inserting barriers to prevent anything placed on top from falling off. However, I've never needed them so far and haven't drawn them either.
 
Then, there is a plain variant without everything and one with honeycombs.
 
The gap between the Case and the Flat part of the Shelf is around 5cm.

One thing that offends me is that I made it a couple of millimeters too short because I added the Backstop so it wouldn't slide forward. I forgot to compensate for that.