I measured actuator efficiencies of TM, IM, and MN stage of ETMX by using LS OpLev.
I excited ETMX from {TM,IM,MN}_TEST_L_EXC @ 6 Hz and measured the spectrum of TM_WIT_L.
Figure 1 shows the measured results of TF from excitations to TM_WIT_L (red:MN EXC, blue: TM EXC, Green: IM EXC).

Current actuator efficiencies from TEST_L of each stage to test mass L motion are as follows:

Converting above TM actuator efficieny in the same manner during O3GK, TM actuator efficiency is 1.13e-12 m/cnt.
According to CAL wiki, actuator efficiency during O3GK is about 4.6e-12 m/cnt, which is consistent with the current value, considering a factor of 4 difference of EUL2OSEM (EUL2COIL) matrix element.