The attached script is a quick calculation of the ABCD matrices from the MC waist and IM1, IM2, IM3, IM4 to PRM that Keita asked for yesterday. It is based on optics coordinates found in T080078-05  (written in 2008)  It doesn't take into account the angle of incidence on the curved mirrors.  
If someone from IO has done a more careful job or used more up to date coordinates, it might be useful to send a link. 

Cheers, Sheila