in the first: plug your mask into a bias node with a second value of 0.8, then plug that bias node into a gain node with a second value of 0.8.  and in the second plug your mask into a bias node with a second value of 0.2, and plug that bias node into a gain node with a second value of 0.8.  bias basically sends your map towards one value or the other (Math node) or one color or the other (Color Math node).  gain affects your contrast.    if you want a harder edge, you go above 0.5.  if you want softer, you go lower.  if you want brighter, then go above 0.5, if you want darker, go below 0.5. 

they're explained much better at Castle Poser.