It's virtually impossible to re-create the original look of the OEM part in this case. Bonnet hinges are also a classic case in point. The reason being, is that these parts are made by cutting & pressing sheet steel, which has already been plated/galvanised, or whatever. So you end up with parts that are corroded in the areas where they were cut.

If you look at really aged pieces, they are rusted badly on the respective edges, so if you then clean them, blast them & then re-plate them, no matter how you do it, they won't look like the OEM product.

Just get then zinc plated by a pro, after you ask a few questions & live with them.

Dr Terry.