The platforms and their fences were painted the same way with a dark red as a base in the inner areas.
The last thing I added was a series of very thinned Skrag brown (I really mean VERY thinned) which was thrown in places where rust would mostly build up.
This makes a great rust effect without having to get the pigments out.
All in all, It worked very well and I managed to finish everything in time (at midnight though) for the day after !
Here are some shots of how the scenery looks on a table :