SQL & PL/SQL

Hi

I would like calculate the following hit ratios against my instance performance metrics

1.Buffer Cache Hit %
2.Library Cache Hit %
3.Redo No Wait %
4.Memory Sort %
5.Soft Parse %
6.Commit %

And I need to know what would be the optimal values against this hit ratio for 900 GB database with Aix 5.3 platform.
if i dont have optimal values with query results. What are all the parameter should i need to tune and how much i need to tune?

Kindly help me on this.

Thanks
Ranga