Paul,
I default the custom property to used to control the time to 1, and that seems to work just fine. What is the source you are using? How many values? Is there an index to support the incremental search?
>On especially slow workstations I have had to increase the _dblclick to 5 in order to get the incremental search to accept two or three characters as one search although the user might type the search at normal speed.