I am re-covering the seats on a 1967 E-type roadster. The seat backs were easy, however the seat bottoms are not. I cannot seem to be able to pull on the top back of the new bottom cushion cover enough to make the top beading on the top front of the seat cover be flush against the foam. Is there a trick to this? Should I staple the front of the seat bottom cover down and then try to pull the seat from the back to try to get it to fit?