autovacuum configuration

Hello:
I have been trying to improve the performance of my 8.3.3 postgres
database, running on solaris 10. I have been playing around with a few
configuration settings, including the shared_buffers because I have
sluggish performance when accessing some very large tables, and the
maintence_work_mem because my database is showing signs of bloat.
What I'm not sure about is how to measure the success of these
configuration changes. In order to test the change in shared_buffers, I
tried running pg_bench and explain analyze on some slow queries but
there is quite a bit of variation in these metrics. I can check the size
of some of the tables that have shown bloat, but that is fairly slow
feedback. Are there better metrics to check these config changes?
Thanks in advance!
Mija

CONFIDENTIALITY NOTICE: This e-mail message, including any attachments,
is for the sole use of the intended recipient(s) and may contain
confidential, proprietary, and/or privileged information protected by
law. If you are not the intended recipient, you may not use, copy, or
distribute this e-mail message or its attachments. If you believe you
have received this e-mail message in error, please contact the sender by
reply e-mail and destroy all copies of the original message.