For some overall graphs, I would recomend getting "smpolicysrv -stats" run in cron/schedule task, at regular interval (say every 20min or so).
Then you can run the smps log analysis on the smps.log files for the last month or week, from the Policy trace analysis module :
Siteminder Policy Trace Analysis
You can then get a nice graph of number of connections/number active worker threads/ throughput that occur over the week or month.
It produces a .pdf report, and individual .png files if you need them, and the latest version does run from the cmd line.
Cheers - Mark