Hey Fabian F.,
I must have missed your suggestion from the other thread:
Hey kashif.c.riley,
if you really would like to author your maps in Photoshop, for instance, you wouldn't want to author them darker and recalculate every time you make a change. It's quite confusing 
What you could do is to create your own working space for Linear sRGB colour. To work just like you would normally you could use a proof setup to view the image in sRGB with a Gamma of 2.2, even if the actual image is linearised.
The biggest benefit I see doing that: You won't get those dark rims around blended colours, which you do get when not working with a linear colour space because Photoshop does the maths wrong somehow.
If you really need to use Photoshop this would the setup I would recommend. If not, just use Substance Painter 
Best Regards
So what I did in Photoshop was to create an ICC Profile with Gamma 1.0. And whenever I need to modify a metallic-smoothness map from Substance Painter I switch Photoshop to that Profile, open the texture, do my stuff and save it.
With the proof Settings under the view menu you gave me a new toy to play with, thx. 
But now I wonder. Since the Unity Standart shader seems to assume sRGB textures (even for smoothness?) do I really need to go this extra mile at all? If I read correctly in the other thread you are not required to "Bypass sRGB sampling" for metallic-smoothness maps. Does that mean Unity expects them to be in Gamma space? Confusion.
Hi,
The easiest and less confusing method is to work in sRGB space. If you work in Photoshop without any profiles or linear gamma, the texture will be interpreted by the shader correctly. I would not recommend trying to work or author in linear space within photoshop.
Unity does expect these maps to be in gamma space and it knows it needs to make the corrections. You don't need to change "Bypass sRGB" as this really only pertains to the albedo map and the specular map (specular/gloss workflow). If you enabled this flag, it would not linearize the map (remove gamma curve), which would result in the sRGB gamma being applied twice. Once in the texture and once in the render view. So if you author in sRGB, then you don't need to worry about manually controlling the linear interpretation of the textures.
I think a good way to think about it is as follows: If a texture contains color then it needs to be interpreted as sRGB. This means it will be linearized by the shader for rendering. If the texture doesn't contain color such as metallic or roughness, then it needs to be interpreted as linear. Its more like its "assumed" to be in linear space. You technically authored roughness and metallic in sRGB, but the shader knows to interpret these values as data.
Here's how the shaders will interpret the maps:
Diffuse, base color, specular : sRGB The shader will linearize these maps for computation i.e. remove gamma encoded values
Metal, roughness, ambient occlusion : linearThese maps are "interpreted" as linear. It means that the shader will not linearize them for computation. Basically, their value is read "as is."
I hope that helps : )
Cheers,
wes