b569rr, just make sure the 1/4 is trimed and fit before you weld at all. one way(if I ever have to do it again) is to use sheet metal screws and screw the 1/4 to the car like that is how your going to leave it. (lots of screws)
That way you can make sure it is straight and secure to the car everyware. Then weld it all up. But I have faith in you. You do great work.