Why do you need to apply a displacement map on your high poly ? If you want to texture your high poly for later presentation you can either unwrap it and texture it the classic way or use procedural textures with projected details. Texturing a high poly can be a really complex task and i would suggest you to first start…
the normal workflow is this: 1. make the hp model (normally all quads) 2. make the lp model (you just need the geometry to keep the silhouette and the shape) 3. unwrap the lp model 4. baking 5. texturing