I believe this very, very closely resembles how yukkuries would look like in real life.
Get a picture of any person, photoshop the nose/ears away, stretch the picture's width by 1.30X to 1.40x the original size. Voila, that's what a yukkuri would look like if we base it on the typical size difference of the head of a non-chibi touhou character with a regular sized yu.