Hey Dan,
I'm not sure about modifying the locator properties, but you could modify the offset used to display match results in your runtime app. In the match results, the GeocodeResult class provides a RouteLocation and a DisplayLocation. The RouteLocation is a map point along the reference network and the display location is the map point with the display offset applied. Before displaying a result, you could use these points to determine a new offset by doing something like moving the display point closer or further to the route point along a line drawn between them, for example.
Hope that helps, Thad