Pugsley,
True! I'm glad you noticed, it's spotting things like that that separate the men from the boys! I haven't got round to doing it just yet but using weathering powders like you say is just what I planned on doing. I'm waiting until the rake progresses though so that they look a little more harmonious when they are all done together, especially the rusted ones.
I acquired another two last week (old RJH version so need modding), onwards and upwards eh?