This is really a very personal question; and it's not so much a JAWS question; but one using a screen reader in general. I take it that you are new at this; and the best suggestion I can make is play around and see what you are most comfortable with. Your use of the word cognative suggests to me that you are overthinking all of this. Some people like reading fast; others prefer regular speech rates. Some prefer one voice for everything; and others may assign a different voice for different things. In short, it takes time to become comfortable using a screen reader as a way to deal with the pc screen. Personally, I try not to overdo adjustments and customization -- but that's me.
