I'm posting here my current settings, that is, the custom INI file that contains the settings as I tweaked them

You just need to put this into a *.INI file in the folder:
C:\Program Files (x86)\Abbequerque Inc\FaceTrackNoIR\Settings
(Win 7 64 bits)
On WinXP, this will probably be something like:
C:\Program Files\Abbequerque Inc\FaceTrackNoIR\Settings
Then, when you launch the tool, go to File-Open, and choose your new INI file

NB: with those settings, the "center" function is set to
SHIFT+ALT+F1, and the start/stop function is set to
SHIFT+ALT+F2.
[Tracking]
Smooth=26
sensYaw=152
sensPitch=58
sensRoll=148
sensX=110
sensY=177
sensZ=242
NeutralZone=3
invertYaw=false
invertPitch=false
invertRoll=false
invertX=false
invertY=false
invertZ=false
useEWMA=true
redYaw=82
redPitch=85
redRoll=100
redX=100
redY=100
redZ=100
[KB_Shortcuts]
Keycode_Center=59
Shift_Center=true
Ctrl_Center=false
Alt_Center=true
Keycode_StartStop=60
Shift_StartStop=true
Ctrl_StartStop=false
Alt_StartStop=true
Keycode_Inhibit=0
Shift_Inhibit=false
Ctrl_Inhibit=false
Alt_Inhibit=false
Inhibit_Pitch=false
Inhibit_Yaw=false
Inhibit_Roll=false
Inhibit_X=false
Inhibit_Y=false
Inhibit_Z=false
[Curves]
Yaw_point1=@Variant(\0\0\0\x1a\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0)
Yaw_point2=@Variant(\0\0\0\x1a@?\0\0\0\0\0\0\0\0\0\0\0\0\0\0)
Yaw_point3=@Variant(\0\0\0\x1a@S\xc0\0\0\0\0\0@\x14\0\0\0\0\0\0)
Yaw_point4=@Variant(\0\0\0\x1a@^\x80\0\0\0\0\0@I\0\0\0\0\0\0)
Pitch_point1=@Variant(\0\0\0\x1a\0\0\0\0\0\0\0\0?\xf0\0\0\0\0\0\0)
Pitch_point2=@Variant(\0\0\0\x1a@D\x80\0\0\0\0\0?\xf0\0\0\0\0\0\0)
Pitch_point3=@Variant(\0\0\0\x1a@T\xc0\0\0\0\0\0@"\0\0\0\0\0\0)
Pitch_point4=@Variant(\0\0\0\x1a@a`\0\0\0\0\0@I\0\0\0\0\0\0)
Roll_point1=@Variant(\0\0\0\x1a\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0)
Roll_point2=@Variant(\0\0\0\x1a@6\0\0\0\0\0\0\0\0\0\0\0\0\0\0)
Roll_point3=@Variant(\0\0\0\x1a@?\0\0\0\0\0\0\0\0\0\0\0\0\0\0)
Roll_point4=@Variant(\0\0\0\x1a@A\x80\0\0\0\0\0@I\0\0\0\0\0\0)
X_point1=@Variant(\0\0\0\x1a\0\0\0\0\0\0\0\0@\b\0\0\0\0\0\0)
X_point2="@Variant(\0\0\0\x1a@;\0\0\0\0\0\0@\x14\0\0\0\0\0\0)"
X_point3="@Variant(\0\0\0\x1a@N\x80\0\0\0\0\0@,\0\0\0\0\0\0)"
X_point4=@Variant(\0\0\0\x1a@_ \0\0\0\0\0@I\0\0\0\0\0\0)
Y_point1=@Variant(\0\0\0\x1a\0\0\0\0\0\0\0\0@\x18\0\0\0\0\0\0)
Y_point2="@Variant(\0\0\0\x1a@=\0\0\0\0\0\0@1\0\0\0\0\0\0)"
Y_point3=@Variant(\0\0\0\x1a@M\x80\0\0\0\0\0@@\x80\0\0\0\0\0)
Y_point4=@Variant(\0\0\0\x1a@V@\0\0\0\0\0@I\0\0\0\0\0\0)
Z_point1=@Variant(\0\0\0\x1a\0\0\0\0\0\0\0\0@\x14\0\0\0\0\0\0)
Z_point2=@Variant(\0\0\0\x1a@E\0\0\0\0\0\0@\x14\0\0\0\0\0\0)
Z_point3=@Variant(\0\0\0\x1a@U@\0\0\0\0\0@9\0\0\0\0\0\0)
Z_point4=@Variant(\0\0\0\x1a@^@\0\0\0\0\0@I\0\0\0\0\0\0)
[GameProtocol]
Selection=5