Does "Use custom controls for this car" box in iRacing need to be checked for the settings I put in the Tuning Menu to take effect?
Settings in the tuning menu will take effect no matter if custom controls for this car in iRacing checked or not. I suggest to check "Use custom controls for this car" in iRacing and set force feed back automatecly. After set in fanatec tuning menu settings that you like. In this case you will not have to play with setting everytime when you change the car in iracing.