I am restoring an old 2000 sq.ft. tin ceiling. I have replaced all the badly rusted panels with new, that I had a tin smith duplicate. The remaining panels I have scraped the loose paint off, some panels 100% off others 100% of the old paint is still stuck on good. Some of the old panels I repaired with bondo and some still have some light rust. What do I finish all of this with ?? I want a pretty paint. Do I prime? Do I paint with Rust preventive paint? HELP!!!!