0% MDH/MDV in the m-s calculator is the correct conversion. That will maintain the same device sensitivity.
The one thing that changes when you scope in is the focal length, which results in a different quantity of degrees being visible within the window that you are viewing the game world through (the monitor). If you scope in, the projection will scale by a certain factor (defined by the fov). The sensitivity will feel incredibly fast if it isn't modified at all (you keep the same cm/360). You simply undo the scaling for the game sensitivity, which is what 0% monitor distance match does. The device sensitivity is now identical to what it was before scoping. The image is different though, the curvature and scale is different, and that is why it will feel different regardless. Your physical input will change proportionately with the change in image.
Amplifying the sensitivity can make it feel a bit better, but at the end of the day it is all preference. The other options in the m-s calculator are different frameworks for amplifying the sensitivity, if you want to scale the sensitivity by some framework instead of just setting a random value.
Since my calc above is based on focal length, you will get the same Control-Display Gain value no matter what FOV it is, if your sensitivity value was converted using 0%. This is why it's a more intuitive measurement for sensitivity, as it doesn't change, while cm/360 does. I wouldn't recommend ever copying someone's cm/360, as you at least have to have the exact same screen size and fov.
For example, my Control-Display Gain is 5. In CSGO, it is 25.5 cm/360. In Overwatch, it is 27.1 cm/360. In the calculator, if you change all the variables to reflect these two games, both will result in 5. If I switched to a 15" laptop, the cm/360 in CSGO would change to 15.6 cm/360, which sounds a lot faster, but it would still be CD-Gain of 5. That fov, within a 15" window, is equivalent to a much, much higher fov on the 24.5" desktop. It is the same as having 73.74/106.26 degrees within the 15" portion of the 24.5" screen, with the whole screen totaling 101.55/130.67 degrees.
Some nice visualisations for fov, focal length, and sensitivity.
Graphical FOV Converter (Focal Length visualiser)
In-depth information on sensitivity in a 3D environment
The result of scaling the sensitivity using 0% MDH/MDV. Your input will directly reflect the change in image.