hi Chris
Hello Chris
I do not know what happened in connecting parts 11 + 12 to part 10.
This should be a smooth and easy connection.
These are pictures of the central body of my model.
All the connections between the parts were connected perfectly without any special problem.
On the other hand Chris, I think I know what happened there.
I took each and every part and closed it completely and then I began to thread each part into the chassis and I got a full match.
You worked a little differently.
you took each part separately and wrap the chassis with it and then close the seam from above and thus you progressed in building the central body.
After looking deeply at the pictures you put....
I see that when you get along with the parts, the upper stitches began to expand until the top seam of part 10 actually became wide, I estimate 2 millimeters.
So I think that this is what caused the mismatch between Part 10 and Parts 11 + 12
Hope you can fix it
YOAV