Expanded the dashboard a bit, and found the time series data helpful in tracking down some nagging performance issues.
The time series charts in these screen shots illustrate two brief performance hits. Since these hits happen at the top of the hours, I looked carefully a the application scheduled tasks and found a number of "clean up" tasks which were not an issue with the DB was small, but with a large DB these "clean up" hourly scheduled tasks can slow the site down.
So, I moved around five clean-up tasks to Saturday and Sunday, since moving these batch jobs to the weekend will not effect the application very much, but does improve performance quite a bit.