Piece by piece.
Thought I would explain my madness to pull off my patches. I work on getting the conture of the quarter traced onto my sheet metal, then I run that line through a set of step dies in the beed roller. Then i cut my tabs, this gives me a line to make my bends to. I clamp my piece with a plate to my work bench so I can make a crisp bend.
The patches will be silicone to the quarter as there only purpose is to keep tire smoke out of the car.
My not be the best way but this is what has been working for me.