I drove IM1 in yaw to look for clipping in the IO Faraday, and did not discover any strong evidence for clipping, however, my calculations show that that's not a surprising result. The beam in the IO Faraday is off center in yaw by about 8mm, but that's still enough clearance that before there is any significant clipping in the Faraday, the beam travels off of the IM4 Trans QPD. The total angle I calculated that's needed to drive the beam off of the IM4 Trans QPD is 2500 urad, and the actual amount I drove IM1 was 2150 urad, a difference of 350 urad, which might be an indication that the beam did start to clip in the Faraday, or could be error in the calibration of the alignment drive sent to IM1.
OR... that was PITCH, which is true, very little evidence of clipping. My calculations show pitch is decentered by about 2mm.
YAW, however, the range that I could drive IM1 was only 1317 urad, only half of what my calculations show would be needed to fall off of the IM4 Trans QPD, which is strong evidence that the beam is off center in yaw in the Faraday, which is consistent with my calculation that it's about 8mm decentered.