Attached a comparison of ETMY pitch optical lever with ISI damped with/without FF01 2 feedforward (HEPI L4C to Stage 1 ISI) engaged on ST1 X-Y-Z
In red : ISI damped, SUS damped filter gain = 1
In green : ISI damped, SUS damped filter gain = 4
In blue : ISI damped + FF, SUS damped filter gain = 3
In pink : ISI damped + FF, SUS damped filter gain = 1