I am the designer and builder of the wind tunnel, so I can answer any questions you may have! Please feel free to post specifics.
In general terms, the reason why there is little in the way of instructions and no photograph is because this step is simple, and up to your creativity. Basically, all that is needed is that you have two sheets of screen behind the honeycomb mesh at the entry point of the Contraction Cone. It is up to you to decide how to install those three components, since there are many different ways you can do it, depending on your materials choices, etc. In other words, I left it up to the imagination of the student, because this part of the tunnel is delicate and so the same instructions may not apply to every person's wind tunnel. Construction results vary from student to student, and so I recommend that you figure out the best way for your specific wind tunnel to have the three components attached at the Contraction Cone.
That being said, it is a bit difficult to do, so please let me know if you have any questions. I'm here to help, so if you want to run some ideas past me for advice, I'd be willing to check them out.
Also, I will search among all my photos to see if I can dig up any pictures that may be of help to you. Photos are hard to take of the Settlign Chamber because the screens and the mesh block the view of each other, but I'll see if I have anything.
O God, Thy sea is so great, and my boat is so small!