This morning all the laser got tripped and the CO2s went down. I used this opportunity to switch on the mask from a cold (ring heater only) state to get the actual OPD of the mask. Beforehand the CO2 cooling down was interfering with OPD measurement of the mask.

We now see an OPD more in line with the prediction (top right plot in main figure). Using 1.1W of CO2 on the mask gives similar level of OPD change compared to Aidan's model, which originally required 450mw. The test was cut short because we needed to get the thermal state ready for locking.