On my mat I have a rubber tee for the driver. If I want to hit irons, hybrids or fairway woods I place the ball about 10cm between the tee and my body. My question is what point do we use to calibrate the R10. Is it the position of the ball (and if so, Do I need to move the R10 and recalibrate when switching between clubs) or is it the mid point between my body and the ball?