Solaris Shared Memory

I'm in the process of setting up my production box and I need to get some
information about Postgres on Solaris.

I have a Sun Ultra Enterprise 2 with 1Gig of RAM that I'm using as my
development machine, and a duplicate machine that will be my production box.
I need to host 3 databases on the production box serving between 250 - 500
concurrent users.  With no changes on my development box I'm only allowed to
run Postgres with -N 8 -B 16, 8 connections and 16 buffers.  If I try to
start it higher it crashes out with an error about Shared Memory.

I've read through the 7.2 manual (7.2 is the version that is installed) and
looked at the System V IPC parameters table, but I'm a bit lost as to what
will make up the proper settings for running this box.  I'd appreciate it if
someone could give me some pointers as to what values would be appropriate
in the /etc/systems file to handle the load that I'm expecting.

Thanks,
Rob