Oracle parameter memory requirements/utilization

Good-day all,

Are there any figures available for the approximate memory requirements that is needed when setting specific DB parameters, as well as a list of DB parameters that affect the memory settings that you need (i.e. SGA to start DB).

For example, the amount of memory required for DB files of 1024 compared to 65000 and processes of 1000 compared to 10000.

Any documentation or information pertaining to the above for db parameters to be able to fine-tune a dbs parameters would be greatly appreciate.

I wish to get a better understanding of how much memory is potentially being wasted on current parameter configs when for example initial specs indicated 1000 processes would be required when in actual fact only on average 300 get utilized with spikes to 500.