Photo Etched Brass Ratlines

[Gunner]

I've never tried it, but I know products like "blacken-it" are made specifically for blackening brass model parts without obscuring detail.
http://www.micromark.com/blacken-it-4-fl-oz,7267.html

Does anybody have experience with this? and would it be a good choice for these shrouds/ratlines?

I use a product called Birchwood Casey's Brass Black which I think uses the same chemicals as Blacken-it, to identify .45 LC brass after I have enlarged the primer pockets to shoot blanks. The black wears off a little after a few firings (which you won't have to worry about) but does not look as good (to me) as spray paint.
But it's much easier to use, just dip a few times and rinse.