After finding good whitening setting, the arm was aligned, I walked the beam on WFSB to find a good offset.

Demod phase was set after finding a good position on WFSB (PIT offset = -0.15, YAW=0). For WFSA I never set any offset.

See the first attachment for the demod phase.

See the second for the spectra after an offset of -0.15 was set for the WFSB PIT centering servo to balance the demod signal peak generated by an excitation to the PDH board EXC A.