After riveting the frame I was concerned that the front of the frame was too wide. The skin protruded. So I clamped down the frame and gently squeezed it shut about 1/8. Spring back was about an inch. I used a pen to mark my squeeze lengths. I squeezed just a little and then checked for plastic deformation. Eventually about an inch of elastic deformation produced about 1/8 of plastic deformation (maybe slightly less) and that gave me a better fit on both sides of the fuselage so the frame skin fits flush with the sides of the fuselage.
