We use a sports turf dressing from a local soil/landscape yard. It is 50% compost and 50% washed sand. This goes down in early Spring after scalping the lawns. We use a large landscape rakes to level it out and then just add water. The compost helps green up the grass and reduces any thatch and the sand fills in the low spots. Sometimes two applications is needed to achive desired results.
When we roll a lawn, we run the sprinklers long enough to get the grass saturated. Then the bumps smooth right out with a pass or two. Don't forget to use flags to identify where the sprinklers are.