I test drove ETMY biases.
PITCH worked well in slow and fast modes. Slow drive was from the IFO alignment screen C1:SUS-ETMY_PIT_COM and
the fast one from C1:SUS-ETMY_ASCPIT_OFFSET
YAW did not. It was always diagonal. It was specially bad with the fast drive. I compared them with ETMX. ETMX yaw is diagonal a little bit too.
The OPLEV return spots on the qpd ETMX and ETMY are big 5-6 mm diameter. The ETMY spot has weird geometry to qpd.