I got the model back to this state, which is sans egregious brush strokes. And here is a three-quarter view to show the roof.
Roof still wasn't right, even after highlighting the panels as can be seen here.
Anyway I took the car the spray shop and applied some new Modelmates weathering dye over the finished model and then refinished the model. This experiment has given me an idea for doing a car using these weathering dyes as the basis for finishing my next box car.
In the process this blemishing appeared on the roof, which was rather surprising, but serendipitously there was a nice weathering article in the April issue of Model RailRoader, by Charlie Duckworth, which showed him doing something similar to represent weathered galvanised steel roofs on box cars. I think a woot for the win is called for here.
The April Model RailRoader issue also has a nice one page piece on Hayes bumping posts too, which is going to come in handy when I get around to weathering my Walthers plastic Hayes bumping posts.