With the Type 30 mostly together the thing that jumps out at me is that I have obviously installed a square screen into a round opening.

The question is how do we fool the eye into thinking it is looking at a simple round screen? I don't know the answer for sure but I have some ideas. Today I tried this. I created a couple of filters.

On the right above is a matte black piece of heavy construction paper with a cutout for the display that exposes just the active area of the screen.  This has the effect of hiding all the seams and the non-active edges of the display. The edge of the cutout is "keyed" to the slots used to attach the blue front panel. I used a bit of tape to hold the cutout in place until the blue panel pieces are attached (left below).

On top of that goes a Lighting Neutral Density Gels Filter (left above), which is supposed to reduce the amount of light getting through without affecting the color (middle below). It looks a little weird in the photo above but in person looks just flat glossy black.  I'm flying blind here.  I don't know how well this will work, but so far it seems to do a good job of hiding the rectangular display frame. I expect this process to be iterative until I get the effect that I want. I am looking for a similar filter in green to better represent the Type 30. 's heritage.

Finally the blue face plates are installed holding everything in place (left below).

Next step is to fire up the display an see if this idea maintains the illusion of just a round screen.