In a regular stove the wiring is in the hollow space underneath the top, shielded from the heat. There are also spill/reflector bowls underneath the elements.I would use the standard socket for those surface element, they are cheap and easy to find. That's the reason for this design, all the parts are easy to find and cheap so far.
For sure the positioning is wrong, it was just meant to look nice (symmetrical) for now.
I am thinking about the surface and support right now. I have a few ideas but I am trying to find an easy and cheap solution.
Make sure your wiring can handle the heat from the elements since there's a lot more in your scenario than underneath a stove top.