yeah, i always tend to put too much oil myself when i change it
the trick for me is to remember what the oil window looks like with no oil there, and then watch it carefully when i add the new oil. somewhere around the 3,5 liters you should see the oil level rising in the window. The window is a bit yellowish in color even with no oil behind it, but you can see the oil level rather clearly when it 'passes' the window. When the level is too high, you can feel the engine 'struggling' a bit, and hence a bit more vibrations. So if you experience that there's a clue. What i would do is add more oil while watching the oil window until you are sure you reached/exceeded the prescribed the 3,75 l. If you do not see the level rising in the window, there's a good chance you have too much oil, so unscrew the oil release screw and let some out, while watching the window. i find it quite easy to do. My problem is i have no patience while filling the engine with oil, and always forget it takes some seconds before the new oil reaches the bottom of the engine and the level rises in the window. So i usually put too much and then watch helplessly as it rises above the maximum level
Also, when you put in a new filter, running the engine might decrease the oil level in the window as the oil is redistributed inside (filter is filled). Hope it helps,
cheers