Prior the 230rx optics getting upgraded, the edgetaper was about 5db
and the beam was about 27" FWHM.  The primary was very over illuminated.
The measurements are from circa 1997 and are summarized
in USER:[HTML.DOCS.MEMOS]BEAMTAB.DAT. 

Looking at the historical sidecab rx focus  curves stored in the VMS
system I believe the data in BEAMTAB.DAT was a correct characterization
of the 230rx system from Oct 1995 to August 1998.   After that
the optics  were changed to improve the edgetaper.

In about Jan 1999, the optics in the 650/345 dewar were upgraded.
The final focus curves and efficiencies of the sidecab rx's were
established on about March, 1999 and are what you see on Jacob's web
page.

To summarize, the 490rx optics were not changed in the last five years;
the 230rx system was changed on about Aug 1998; and the 345/650 system
was changed on about Jan, 1999.   Before the changes, BEAMTAB.DAT
was the most accurate characterization of the system that I know of
covering the recent 5 year span you are interested in.