bq27541-v200 DF setting when I use 80% capacity of full battery capacity

I want to use 80% of battery capacity as 100%.

In that case, what parameter should be changed?

Is it the following parameters? If there are any others, please tell me.

-Charge voltage:  setting lower voltage than 4.2V

-Design Capacity:  setting lower value than capacity of cell datasheet 

-Qmax: same as above "Design Capacity"

Even if there is the GG file after 4.2V learning cycle, should the learning cycle be done again at lower setting?