Hi Zuzana,
thanks a lot for the extensive answer!
I read the help section today of course… 
I think I got it now. Matches Count defines the basis for the calculation and Minimal Matches caps only the display of the result. So if Matches Count is set to 50 but Minimal Matches remains 100, then the display won’t change.
Concerning Maximal Count: I think it’s important to mention that the value will not result in fewer lines, just move the color threshold for red down to this number. That means all image pairs with more than e.g. 1000 matches will also be red.
So Connectivity means how many “partners” each camera has?