HFM Memory Utilization Settings

Hi Experts

Could you please throw some light around (suggestions,best approach) how to start with the exercise of tuning the Memory utilization for HFM applications? (App specific tuning)

Oracle Admin guide provides recommendation on memoy setting for large applications (Max No. Of . Data Records and Max Data Cache Size )  based on available physical memory in the server.If multiple applications will be active, then divide the total physical memory installed on the server by the number of applications to arrive at the Available Physical Memory for each application.

On the other side I read blogs where experts suggest app specific tuning based on the measurement of database size (Data Extract, Free LRU etc).