Launch Control uses Analogs 1 (clutch1), 2 (clutch2) and 3 (clutch adjustment).  Manual clutch adjust must be set to 0 to use analog 3 to adjust the biting point. 

If you do not have analog 3 connected, you can use the manual clutch slider to set the biting point. 

Note than when you set launch control to enabled it sets Analogs 1-3 to Analog. 

1 clutch gets to the biting point, the other clutch moves the full movement, adjust moves the biting point.