In these two weeks I optimized few times the IMC angular offsets, in order to reduce the coupling of beam jitter to intensity noise. Attached the MATLAB script I used to decide the optimal offsets. It grabs a period of data (of the order of some tens of minutes) and plot some scatter plots of how the band-limited RMS of intensity noise (measured with IM4_TRANS) depends on the IMC angular DOFs. The script parameters are set at the beginning, and the attached one shows the typical values I used.

The typical result is shown in the attached picture. In this case one can see thay intensity noise tends to be samller for positive values of DOF_1_P and negative values of DOF_3_P. My conclusion would be that we need to add an offset of about -20 on DOF_1_P and about 2e-3 to DOF_3_P. I didn't want to interfere with the ongoing locking activities, so I didn't add those offsets now.