Looking in oem management views like mgmt$metric_daily, current, etc for what database is consuming

Our environment has many oracle 12c databases on a windows 2012 r2 server and at times performance suffers in multiple databases at one time. 

I understand how to drill down into performance issues one db at a time but I am looking into the oem mgmt. views like mgmt$metric_daily, mgmt$metric_current, mgmt$metric_hourly, gc$metric_values_daily to try and figure out what might be the bottleneck from what db causing the biggest performance hit on the db server.

I see many metric columns that have information like Load, cpuUtil, wait events, etc that I feel probably can help me narrow down which db is consuming the most resources, etc on a given db server, but so