I picked a few pictures to show the riveting sequence I used to avoid the flap trailing edge being curved. Also you can see that I replaced the hinges with the extruded ones. I selected the extruded because I heard that those with bend hinges have had broken loops over time. I was told the extruded hinge, although expensive were much more thougher.
The trailing edge came out straight as an arrow. I will show picture of both flaps next week.
I still have to trim the upper skin on the inboard end but the instructions and drawing are not clear so I refrain cutting it yet. You can always trim off but cannot add once it's cut !