Widowmaker DOES have a separate sensitivity for zoomed in scope. You have to select Widowmaker at the top right("All Heroes") selection, and "Relative Aim Sensitivity While Zoomed" will appear under the HERO category, below the reticle.
At 103 FoV, relative aim sensitivity has to be 38 to be equivalent to unzoomed sensitivity in screen distance travelled. (Explanation by someone else here)
Oh, there was a second page detailing it. Anyhow, 38 is what you're looking for if you want equivalent to zoom_sensitivity 1 in CS:GO, as that makes it the same movement to cover the same screen distance regardless of scoping.