This design is for PCs that are in a cabinet out of sight. 

It uses four #8 Lath Screws with the exact ones being Everbilt SKU 540509.

All you have to do is mirror (X-axis) the main piece in the slicer for the other half. Then print two of the rods in order to maintain spacing when installing the bracket.

I printed this object in PLA, but PETG might be a more durable option