I lined the entire optical cavity of my Mits WS65857 with black felt (around the three lenses. However, I only partially lined the left and right sides. It became difficult to fasten the felt towards the top 1/3 of the cabinet, without covering part of the screen. Also, I was fearful that using a lens hood could obstruct the light output of the lenses onto the mirror. I couldn't determine from Paul's pictures whehter the hood should be fastened parallel with the lenses or angle in (fastened on the thin top part of the wood). I'm sorry, but it's hard to describe my confusion. Regardless, how important is the lens hood and completely lining the left and right portion of the cabinet? Is the lining the optical cavity sufficient?