If your 65 was anything like our 66, you may well find rust on the lip of the outer wheelhouse, especially at the lower front and rear "corners" of the wheel opening.  We took the flange/lap approach to patches on the wheelhouse lip, and butt welded patches to the quarter skin areas around the wheel opening.  The thought being it is easier to work single thickness areas with a hammer & dolly, where visibility is important.  My son has ok welding skills, and that was the approach he was most comfortable with.