Georgia took some OMC scans today, Elenna documented them in alog 62507, here they are plotted together.
The frequency axis is calibrated into Hertz using the 91 MHz peaks.  There is some nonlinearity to the PZT, as expected.

There appears to be loads more carrier at 50W with no DARM offset, also to be expected.
The 9 MHz sidebands are hard to see here.

We can try turning up the 9 MHz mod depth at high power.
Georgia suggests trying putting in a MICH offset to see if that makes our contrast defect worse.

Code to make these plots is here, and only requires the gps_start time 
https://git.ligo.org/aligo_commissioning/labutils/-/tree/master/omc_scan
another in the long line of commissioners past who have make an omc_scan directory.