I had an X56 hotas from brand new it was sloopy around the center even with a dead zone of 8 half the time the AP would not engage, spent more money on a vkb evo space edition the problem hardly ever happens, don't use any deadzone or curve now.
With the A10c11 the X56 was not as much of a problem so long as you were in pitch limits the barro alt would hold, can't remember exact limit +/-3 degrees?