Define Pressure Test Parameters in Pressure Decay Leak Tester

hello everybody! This is my first discussion, and I am hoping that someone with experience can help me.

I have to define the test parameters for  leak testing  of Single Use bags used in Pharmaceutical which volumes range from 50 ml up to 500 ml. 

I am using the most popular leak pressure test method used for On Line Leak Testing in Manufacturing which is Pressure Decay (e.g USON Leak Tester). 

To start I am focused in One Size only. The leak size has been defined by the customer as 20µm. 

I don't know how to calculate or how to establish the settings for testing. These are the settings that I have to calculate: 

Pressure: Which pressure I should use to start with? or how can I calculate this pressure having the Leak Size of  20µm?

Decay: This is the most important setting I think 

Charge Time

Settle Time

Test Time

Pressure % Tolerance

Bleed Timer

Fill Time

Please any help that you can give me will be highly appreciated. 

Note: I have already read any possible study research, article, publications, forums discussions available in internet (hours of research) but I can't find anything specific on how to establish these settings. 

Thank you!