Hi Carlo,
You will find the dead zones challenging on the X56 in my experience when it is in factory spring setup due to the poor centering with the factory spring (I also use it still currently) my recommendation is to install an external spring modification, remove the factory spring and you will find you can set minimal dead zones and good curves depending on the aircraft you are flying (curves vary between aircraft depending on the responsiveness of the control surfaces and flight model) and it removes the issue with the center play the X56 has.
I used the following as the basic guide to modifying mine (although I adjusted it a bit to suit me):
After the modification I generally run a dead zone of 2 and a curve between 12 and 20 depending on the aircraft.
Cheers,
Matt