Fuel tank ribs test assembly and fit to main spar

It took a bit of hammering of corners, use of bracelet pliers, and sanding of high points to get the ribs to fit.

There are hole match issues for the left hand fuel tank topside, around the transition from the front- to rear facing- main spar flange. The mismatch in this case is about 1mm. It is expected that upsizing in this region to 4.8mm rivets will address most concerns.