I did just the slightest bit of sanding on the fuselage side of the wing
root fit and the one piece wing fit snugly. A tiny amount of Perfect
Plastic Putty filled some small gaps. The cockpit
was fit from below once the fuselage was glued together. It is
important to test fit the cockpit while fitting the wing, if the cockpit
is not sanded on the upper edges of the sides or
placed a bit off it will make for some problems fitting the wing. I
did a lot of fit checking of the wing/cockpit/fuselage with all of those
parts just held together with Tamiya tape.