Nice tips... I do similar.
I also paint the bottom of the master cylinder silver or steel. Once
dry I go over the whole thing with a black wash. It gives the bottom
that dark silver look like those cast replacement parts and tones down
the bright shine of the cap for a more aged look (but not too dark LOL).
Or the custom approach - black master cylinder and chrome cap.
Sorry I first missed this thread and then had to think about how I do it.
Oh oh... sign of getting old?
Nah... I'll blame it on my meds.