Dpi mouse acceleration in mouse menu

So how much dpi does the mouse option sensitility and speed for mouse and for keys actually increase or add/take away form the "normal " mouse/ keys accerlation or speed ?

Is it like it says ?
if the middle says it is 50% (mouse sensibility) does this mean if i got 8000dpi on the mouse and have also the middle option in the Windows option(mouse accerelation), that i get 4000 dpi?
Or other way around i got 4000dpi and put 100procent in the starcraft RM menu i get 4000dpi, etc.?
And how does speed affect here?

And the options mouse sensibility on/off
use mouse scaling
Hardware cursor

how do they affect exactly …
Hardware seems clear, but the rest?
How do i do to exactly calculate dpi for a certain mouse if iam already accustomed to 8000 dpi wth 50 % sensibility and 50% mouse speed… IF i want to change mouse, but certain mouse doesnt have 8000 dpi…?