The idea of the pictures Bryan is to show modellers what rust and varying surface effects actually looks like. Many modellers take on the task of weathering without studying the real life examples to see just how they form.
Weathering, as always, is up to the individual and I would always suggest that less is better but if you are going to create rust effects than at least refer to real life subjects for your guidance.
Also a lot depends on your subject and the scale you are working at. Most rust on a 1/128th warship would hardly be noticeable however every single picture I have seen of an early 20th century coastal steamer had rusty and dirty exteriors and this would be readily visible at 1/35th scale. My own point of view is that vessels of that age were not painted with spray guns, they were touched up over many years to the point where the surfaces were a multitude of textures and hues. A perfectly sprayed hull finish may be what you are after if you are trying to achieve a yard model but for a realistic representation you have to look at weathering the surfaces. To this end I have deliberately not sprayed the hull or the accomodation. I have used a small flat brush, similar in size to the scale real one and I have varied both the colour and the amount of shine.
Mine will probably be considered as heavily weathered but, as a direct copy of the original would look quite a mess, I will be trying to find a balance between what is acceptable for a model and what would have been reality.
As for scuppers, I completely agree that the streaks drift towards the stern which is exactly the kind of effect the pictures are supposed to make you think a bit about.