After some discussion with Tara and David, it became apparent that it would be wise to take RIN noise and EOAM-to-PD transfer function measurements over a wider range of frequencies than was done previously.
For these measurements I'm using the same PDA10CS as before, although here I've got 0.48 mW going onto the PD (i.e., no ND filter), and the PD's internal preamp is set to 10 dB. The dc output voltage is 1.7 V. I did the RIN measurement on the SR785.
For the transfer function I used both the SR785 and the HP4395A. Because the HP4395A has 50 Ω inputs, it shows an extra 6 dB attenuation which I've undone here (since the ISS is all high impedance). The transfer function is well described by a single-pole rolloff whose DC amplitude is −0.0148 V/V and whose frequency is 330 kHz (shown in green below).