I do all the gaps. Helps to cut down on flutter and fuel seepage into the hinge line. Cut a piece about 1" wide and crease it tightly. Deflect the control surface fully and place the crease in the gap. Iron one side then the other. After a little practice, I learned to iron both side at the same time. I trim with a single edge razor blade. Use a NEW BLADE EACH TIME and be careful to hold the edge angle parallel to the surface so it doesn't dig into finished covering. Hit the edges with a hot iron and they'll disappear.