Critical or Baseline Metrics for DB and FMW Monitoring

My team supports multiple business units with solutions built on Oracle DB and FMW [e.g. WLS, SOA, IDM, OBIEE]. Since OEM Plug-ins for DB and FMW supports a large list of available metrics for monitoring, I am looking to define a minimum standard set of metrics for each product [e.g. DB, WLS, IDM, OBI]  which are critical to the health of a product, and which can be offered by default. The individual business unit can then build on top of these default standard metrics, and then add other metrics specific to their solution

I already have the OEM documentation for all the available metrics. Has anyone done an exercise for a critical subset of metrics required, or if there is a documentation which outlines the critical metrics to be monitored for each FMW product and the DB?