Well I have myself a tank cover now. I did find some metal mesh with 1/2" by 1/2" squares. I think it was called garden mesh. I made a wooden frame and then attached it. Turned out pretty good and worked fine but I found it was too bulky. Then I found some reflective eggcrate at HD. I bought a sheet (kind pricey) and trimmed it down into to separate covers (one for left and one for right, they sit on the center brace and tank trim). If there is any light being blocked it's not much. Here is a pic of one after it was trimmed to the right size,
