I am doing one and get those puckers too. I folded the football in half and pinned it to the center of the arc, then went to each end and pinned it so the football had a little ear sticking out. Then I took the part between the middle and end and bowed it up until it "fit", pinched it and then pinned it with the pins angling slightly. It worked much better.
I would take a pic since I have on I am working on right now but my camera's battery is dead!