[cwl1979]

As a suggestion, I would start where the rivets are still present and drill out 2 at a time and replace with new ones of a slightly larger size, to get a gite on things. Make sure you get all the "goop" out that you can for the best possible mating surface. If you have a way to get something beside the coach you can push against that would be great so you can close the gap while popping in new rivets.