Hifiberry DAC and volume settings help

I’m using the Hifiberry Doc plus. After doing some search I am still not sure how to set the volume levels and will be glad for some clarifications.

  1. In Volumio volume settings, I select hardware. What is the following setting? Should it be digital? Analog? Or something else?

  2. I read in one post that it is recommended to set a maximum volume. Why is that and how should I set it?

  3. In alsamixer if I choose the Dac I can see many possible options I can change (for example FIT de-emphysis etc…). Are those settings effective or Volumio has it own set of settings and it ignores the alsamixer settings? If they are effective, what should I set?