@Valerio I believe you might need a bit more time with your well equipped 41 (DS?)
Not sure what you are saying about being able to sleep (3) on the deck in front of the bimini? not sure I would want folks sleeping there.
We have spent many hours sailing in 20+ winds and the 41DS handles this amount of wind with ease, yes you must reduce sail area to achieve optimum speed with minimum weather helm. We routinely see 6.5 kts sailing a beat with wind in the 20's and an almost neutral helm. The 41 DS achieves her theoretical hull speed while reaching this is where the Sapphire really loves to sail, we have on several occasions exceeded hull speed while surfing in 8-10 ft seas running DDW.
I am also confused by your comment, "This is a boat designed as a show off at the harbor so a lot of space is missing to storage things" which contradicts an earlier statement, "If you by like mine a very well equipped boat you can have almost everything onboard"
We find our 41 2-cabin design roomy with plenty of storage for provisions, we did not purchase our boat with the idea of having room for more that the wife and I during long trips, although 4 adults could spend extended time aboard with relative ease.
As for the main cabin, the queen sized berth is perpendicular to the boats center line, on a port tack you will find your toes higher that your head and with this, one might want to switch ends of the berth, more importantly is that the berth is perpendicular to center line which would help keep its occupant in the berth when healing, yes this would be an issue in very large waves, waves I hope I am never exposed to while making a passage.