Exterior: If you scan a good side view photo (full scale) and scan in Vailly's plans you'll see the tail isn't high enough relative to the main cabin and it's too thick throughout the fuselage cross sections. The Vailly flaps don't have the right angle at the fuse and there's too much wing dihedral. If you look at the fuselage where it transitions from the aft spar pickup bulkhead to the main tail cone, nobody's hit it right. They're not straight lines on the full scale Birddog so straight longerons aren't going to give you the true contours.

Interior: As previously mentioned, the fuse longerons are incorrectly placed and the cockpit kit can't hide that fact.

Okay, I'm picky but to be truly scale, an aircraft should look right from every angle, inside and out. Vailly's is nice but one couldn't take a photo of the best rendition and pass it off as the real deal because it's not "right". The best efforts of a scale modeler are for naught if the basic airframe doesn't have the correct lines and contours.