The heated bed would not lie flat, so the retaining screws provided with the QU BD kit were not enough - they just prevent horizontal movement. I kludged up something with longer screws, washers and small blocks of wood, but the screw heads were horribly in the way. This is my solution. You'll need two left and two right retainers and four M4 nuts to go along with the M4 screws in the kit.

This was a challenge to build, since there is an overhang no matter how you lay it out. Since I'm still figuring out the parameters, my print quality sucks - yours will probably be better if you know what you're doing :)

I have a sheet of PEI on my bed, but the thickness should not make much of a difference.

Model in FreeCAD, feel free to remix.