In th context of hanging a new SR2 mirror after O3 I went to measure the available space on the +X side of the vacuum chamber. This information is important in order to determine whether we need to remove the POS table to make room for the suspension assembly frame.
The drawing attached shows that in the original assembly place on the -X side of the chamber, the space available between the large outer frame and the assembly frame was approximately 34 cm, whereas on the +X side it would be about 17 cm. Considering that our feet tend to be larger the 17 cm, this means if we install the frame on the +X side, we wouldn't be able to stand on that side to do adjustments to the payload.
The position of the frame is determined by a supporting horizontal beam on the second floor of the clean booth and the height of the assembly frame. On the +X side of the chamber we wouldn't be able to extend the clean booth and move the frame away from the chamber.