FSM settings -- how to tell if they are working?

We have both test and production databases, about 10 GB total in each.
Recently, I learned about "max_fsm_pages" and "max_fsm_relations". To get
a feel for what changing these settings would do to our production
database, I set the following values in the "test" database:

max_fsm_relations = 100
max_fsm_pages = 350000

but left the production server alone. How can I tell if these new
settings are having any effect? How can I determine if these numbers are
the best choices?

We perform full vacuums on each of 103 tables every night (including many
very small tables, which exist only to provide references for foreign
keys -- "code tables").

--
Jeff Boes vox 616.226.9550 ext 24
Database Engineer fax 616.349.9076
Nexcerpt, Inc. http://www.nexcerpt.com
...Nexcerpt... Extend your Expertise