I'm glad that somebody noticed the issue... it would've been embarrassing if it had gone past the painting stage looking like that!
I decided to work on the upper wings next and see what it would take to close the gun/ammo panels. I'm guessing that these panels were designed to be posed open to showcase the machine guns and ammo belts because the fit in the closed position isn't great.
The edges around the panels are very thin, which is good if you are posing them open, but the raised lip around the edges of each panel opening are deeper than the panels, causing them to drop below the surface of the wing when fully pressed into place.
There are different ways to address this issue... I decided to ring the openings with stretched sprue, effectively reducing the depth and bringing up the panels to the same level as the rest of the wing surface. It took a few tries using different sizes of stretched sprue.
I also added a shim to the free floating connection between the two panels to give that joint more strength. The last thing I want is to have a joint crack during painting because of a weak glue connection.
I'll let this sit and dry before I permanently weld the panels in place using Tamiya Extra Thin cement.
There are still some gaps but that's ok as long as the panels are level with the wing surface.
