The image on the left is a an example of a uniform worn in the Franco-Prussian war looks rather nice.
I will expand on my comment on differences what I mean is how many of the NW assets can you use and still keep realism, examples of
-Major European powers in a similar theater of war. (Can you use the same the same buildings?)
-Black powder is primary propellant as well as paper cartridges still used. (Can you use the same smoke effects and sound?)
-Line formations.(Will be attractive to current community)
-Fairly similar uniforms.(Can the same backpacks, cartridge cases still be used and could you use a large amount of NW uniform assets?)
(Also I never released the full extent to which the union and confederates did imitate French uniforms, the guys below do look a lot like the 14th booklyn.)