Retraining the MCL filters resulted in a slight improvement in the performance. Compared to no FF, the RMS in the 0.5-5 Hz range is reduced by approximately a factor of 3.
Attachment #1 shows my re-measurement of the MC2 position drive to MCL transfer function.
Attachment #2 shows the IIR fits to the FIR filters calculated here.
Attachment #3 shows several MCL spectra.
Conclusions + next steps