what i did when i patched the quarters on my camaro i started with the bottom edge of the quarter beating in the shape with a body hammer and a anvil/dolly then you have to cut some releif cuts so you can bend the panal around the wheel well and bending these over with pair of pliers or what ever works then cutting the exice of with some tin snips. once you have the basic shape of your corners. then just trim around the rust and instead of trying to make the panel fit into the whole make the hole fit the panel by just marking it with a marker and cuting it out with a die grinder makes the patch fit nice an tight. thats just kinda a run by but maybe found something helpful