I have calibrated ETMX and ETMY actuators and added a template armSpectra.xml into /users/Templates directory.
Template shows control and error signals of both arms. Procedure is standard: calibrate control to meters and match error based on UGF measurement. XARM UGF: 200 Hz, YARM UGF 210 Hz.
Noise level at high frequencies (>100 Hz) for YARM is 3*10-15 and is factor of 3 better then for XARM. Servo gains are in the same ratio. I think there is less light on POX than on POY RF PD because I checked phase rotation and analog gain. I assume transimpedances are the same.