Am starting my 55 Olds 88 project and the car is really solid but have some rust holes in the outer roof skin near the drip rail. This was due to the car being a rodent resort for decades. The structural channel areas around the windshield and back glass are pretty rust free. Can these areas be patched without ruining (warping) the roof? I was thinking of using POR15 on the inside after cleaning out real good. I poked around and the areas are not more than a few square inches each. I am thinking it won't be easy (or cheap) to find a complete donor 55 88 2dr sedan roof. Thanks!