[brucepick]

Have a try at a plexiglass upper grill block. I like mine. You see the "H" logo through it. Any sheet material takes patience to cut a good fitting panel. I suggest cardboard or something cheap enough.

My plexiglass block is attached with four stainless screws and washers, one at each of the 4 outer corners. Maybe you can invent a way to attach your ock without leaving screws showing.