Sorry to be blunt tricky but you could have modeled the whole thing in real geometry in the same time it took me to read this thread.
Displacement is a complete waste of time & effort in this situation.
Simply create the profile as a line & extrude , then slice/cut to shape if required.
You will actually end up with a LOT less geometry [& no artifacts I may add] that way & a LOT less headaches.
Cheers