Played a little bit with one of the Wala XL photos.
I had said that the grey panels were probably meant to be a beak if the eyes were going to make any sense on the panel layout.
So here is a photo where the grey panels have been changed to yellow. That would be a no cost change to the design probably. Adding the nostrils might cost a little teeny bit more. But the eyes now look like they belong. Other color schemes using yellow might need to be reworked.
I've sent an email to Flying Wing with the photo as a suggestion for future builds.
You people with one already, could just draw in the nostrils with a Sharpie™.