Milter-greylist

Howdy all -

I want to implement milter-greylist in a relatively large environment
(about 6000 e-mail users).

I use milter-greylist on a bunch of smaller sites with no worries, but I
want to make sure that I'm not going to piss off my client by installing
something that is not stable.

Any issues running milter-greylist under a pretty heavy load?  The
servers are dual processor (2.2GHz Xeon) Proliant DL580s with 2GB memory
each, running RHEL 2.1 ES.  The version of the Sendmail RPM is
8.11.6-28.72.

I have been running 1.6.  Should I continue to do so or risk 2.0rc3?

Thanks!
Thomas Cameron