Sledgehammer to crack a nut

I find it very difficult to distinguish between The Uncertain (Hoplodrina octogenaria) and The Rustic (Hoplodrina blanda). Everyone I speak to has a difference favourite method to tell them apart, but the shinyness of The Rustic compared with the rougher appearance of The Uncertain is a consistent suggestion. I think I've just about managed to capture the shinyness on the forewing in a photo (same lighting).   
   
I took a closer look under the microscope at the scales in the kidney mark on the forewing and it is possible to see a difference - The Uncertain has quill-like scales which point forward and presumably contribute to the rough appearance, whereas the scales on The Rustic have a flatter and more "sleek" appearance (Extra).