For being such a tiny part... this dang thing takes some thought and time. I think the directions need to be changed. I followed them even though it seemed the wrong thing to do... and it was. The sixth step is to RIVET the trim tab horns onto the skin. For the next 6 steps the darn horns are in the way. (They easily could have been riveted much later in the process.
The bottom portion of the trim tab is a bit wavy... but the top looks great. I actually found bending the end tabs interesting UNTIL I started the side with the trim tab horns. Again, they were in the way.
