I was given an estate roof rack frame for free, the galvanised steel was fine but slats were long rotted and the mounts weren't galvanised, with expected crumbly results.
Filled the rivet holes, primed and enamelled, and made some new pine slats, suitably dyed to contrast. Slats attached by pipe clamps on the underside so no screw or rivets in top surface.
A couple of period-correct thule roofbars give a solid mounting on a saloon. No problems with bonnet or boot or driver's visibility.
Expedition time!