Thanks 3dS. There are a couple spots I am going to go back and annotate.
At the point I apply the bridge between the inner and outer shell you notice the bridge covers the entire surface. Then I grabbed the bridges offset control and scrubbed it but could not get it to bridge. When that happens it's almost always a normals issue. So to show that I selected two opposing edges and bridged to show the "bow tie" non-manifold geometry you get when bridging surfaces with crossed normals. I model with two-sided lighting off so a quick glance you can also see the inner surface was black meaning it's normals where the wrong direction. So all I did was 1. seperate the geo, 2. reverse the inner surface direction, 3. combine, 4 select the two edge loops and bridge.
Here is a render of the final brick without any displacement....
I am not satisfied with the displacement results I am getting and will start a new thread to discuss this so I do not take this thread in a totally different direction.
Once again I am glad you are finding the video useful. I will reproduce it with annotations and replace that one soon.
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675