For my 1/1000 I used aluminum adhesive foil tape applied over the ridges on the insert. Had to sand the ridges down until almost gone though because of the tight fit. My bussards were lit which is why I preferred foil; it blocks the light better.
The Smithsonian Big E has the fan blades looking like a silver/aluminum color. However, you have to take this with a grain of salt since this was part of the 1991 restoration that fans are not happy with. I remember seeing them in action in 1991 which was impressive, but since it is not operating now, you can clearly see them.