A test fit showed that the fins segmented the rainbow stripes on the engines so that they didn't look good any more. A monochrome stripe looks a lot better in this case. Because I had already assembled the engines I isolated the stripes from the original plans, recoloured them and glued them onto the engine sections. This idea was so simple and effective that I decided not to add the complete recoloured engine section to the final plans but the recoloured stripes only instead.