I liked the original design but needed a nice mount for my Kossel beams. So I added some padding and holes for M3 screws. Screw heads should fit inside and let the PCB slide in (worked in my case). Pads are angled so they will print OK without any supports.
I've also added a large hole to get the wires in. The whole is located between Kossel beams so you can pass through all wires including LCD ones.
If you need to mount it on the other side of the pinter - use the "opposite" STL and let me know if it works.