Looks like the spot position on PR2 is about 0.3 mm above center in pitch and 0.5 mm to the left of center if facing optic HR side. This is different than what Louis measured a few weeks ago in alog 91701 and also different from the beam spot in O4.

I locked on PRMI and injected into pitch and yaw on PR2 while adjusting the A2L gain on M3. I looked for the moment when the transfer function sign flipped as indication that I had reached a minima. Screenshots attached. I determined the following gains minimize the pitch/yaw coupling to PRCL:

P2L: -0.2, Y2L: -0.3.

Following the calculation I used here, I measured the numbers reported above. The directions are based off of comments from a script by Jenne:

"# Y2L signs mean that if you are viewing the optic from above looking down on the optic, with forward = HR face of optic and backward = AR side of optic, then +Y2L gains mean beam is on the left of center. -Y2L gains mean the beam is to the right of center.