not sure if you saw the new sideshow rex...but it may help you with this...as far as they used a regular Range Finder and the stalk is mounted externally similar to how you have it but the stalk is the same as a Fett also. The Fin has a silver stripe down the middle of it...dont know what you used to mask with but I think you should go back over the blue areas with sandpaper to give it a weathered look it looks painted right now and poorly masked...