Thanks so much to you all for your comments and support! I hope I can get close to your expectations:?)
In terms of weathering uniformly, my fight will be to not make the beautiful engine too pretty,
but I can't guarantee more than a bit of crankcase grime:) I will take this thread to the Automotive Group.
I'm not the best at stopping to take photos but I'll try. I have managed to rope wrap (and stain) the leaf springs and replace as many of the self tapping (?) screws with actual brass hardware from Model Motorcars. This also adds some strength to the assemblies. I use brass pinning on all my builds especially aircraft.
3 attached images. Click to enlarge.