Hi, i had also some trouble with my DFGT, so i tested several settings for the last week.
Now i have found out the best working settings for me.
1: deleted the game profile for shift2 in logitech profiler
2: reseted the global settings in logitech profiler to default
3: Increased the steering lock in logitech profiler to 900 deg.
4: Saved this settings and minimized profiler
5: Selected the DFGT - seperate pedals profile in Shift 2 options
6: Set the advanced options in shift2 (see the picture below)
Now i have no deadzones for steering/gas-/brakepedals and force feedback works fantastic for me. Give it a try, for me driving shift 2 is 1000% better then before, especially critical cars like the lotus exige/Dodge Viper are more driveable because you can better dose steering and gaspedal.