How much do people generally raise pre-flop when heads up?

Let's say blinds are 100/200 and you each have 4000 chips.

You are dealt Q8o or some medium hand in the SB, and decide to attack.

I would normally raise it to about 500, maybe 600. I don't like raising just the minimum, becuase I know that I will almost always call a minimum raise when heads up. Maybe I'm on the wrong track though. Maybe a minimum raise is the way to go, because of the risk/reward ratio....I just can't see people folding to it that often.

How often do you just call in the SB heads up? Ever? With monsters/medium hands or both?

How often do you raise from the BB vs. a limper? How big of a raise relative to the blinds?

I'm still working on my heads up game also. I get too aggressive short handed. Eventually somebody gets a monster hand against me and I try a bluff that can't work