After our last failed attempt to transition to ETMX in low noise, I thought the problem might have been a pitch instability at 2.8 Hz.  This partially motivated turning down the CSOFT gain.  I copied the L2 L2P filters from ETMY to ETMX after talking to Kiwamu and remebering that we haven't actually used the L2 length to angle decoupling on ETMX. 

TVo and I again redid the 75% transition, measured the OLTF down to 10 Hz and saw that it agreed well with the measurement when we were completely on ETMY, and tried the full transition.  We stayed locked for about 60 after the ramp ended, starting at 20:41:40 UTC on August 2nd, then unlocked with a similar instability at around 2.8 Hz. 

We probably need to do measure the OLTF down to 2 Hz, or measure the crossovers.  This time the problem didn't look like pitch, it didn't show up in the oplevs (the L2P decoupling worked at least). 

The attached screenshot shows the spectrum before and after this test, as well as the spectrum after the reboots described in 37969