Its under profile/options/general
There is a sensitivity stick adjustment for ailerons,rudder, and elevator.
As for the dead spot,my x52 has none so I can't help you out on that one.
I know when they patched the Ps3 ver, that added adjustment for the dead zone, so if once you make adjustments in the options,, if you still have problems you could maybe post about it on the DEV forums. Or you could buy a new stick ?
Best of Luck, Desode