Nice one H ! Long time since I've used that method, but you're right, it works wonderfully.
Just looking at the gap in the wing leading edge. It appears that it wasn't joined fully, which normally points to an obstruction inside, such as a raised piece of 'flash' from an ejector pin mark or similar. The 'porridge' seems ti have done the trick, but you'll probably need another application, to avoid a visible indentation which will show up under the paint.
BTW, by 'soft' pictures, I meant not quite sharp, and with a colour cast and ever so slightly dark. This is due to the camera having problems focusing, partly due to it picking up the real 'colour temperature' of the artificial light used for lighting the subject.
Just set the 'White Balance' for the lighting being used, refering to the instruction manual, and try to get the light fully on the subject, avoiding a shadow on the parts being photographed. The light will probably look bright enough to the naked eye, but the camera sees it as it actually is, and will record the dark areas accordingly, which, in turn, affects the auto-focus. It's also better, if possible, to use a light-coloured background, as this will enhance the subject's outline, and provide additional reflected light.