I found 3 sources of 2000 sunfire/cavalier shop manuals on e-bay. Would these cover a '99 and would they show how to repair the convertibles?
there weren't a whole lot of changes (if any) mechanically between 1999 and 2000, so yeah, it should.
I see at least 6 sources on eBay for the proper 1999 shop manual, so I would just get the right one. And yes, they cover convertibles.
Shop Manuals, Brochures:
www.kenmcgeeautobooks.com