The OM dither lines (around 1.7kHz) are not being used, so I turned them down by a factor of 10.
H1:OMC-ASC_P1_CLOCK_GAIN = 0.1
I'll leave them on to make sure that we don't run into DAC bit-noise problems (e.g., no HF signal gathers the DAC noise around DC, which is not fun).