Pictograph

I want to create a pictograph that allows you to show an icon that represents a fixed number.  I have tried using the Infographic Designer and the Walker Pictogram.  Both are capable of visualizing the data with icons but I can't seem to get either to do exactly what I want.  I have a metric where the total is 900.  I dropped in my category field.  A summary of the metric by category is below.

Category 1 - 600

Category 2 - 250

Category 3 - 150

I want the icon to always represent 10 units.  So for Category 1 I want to see 60 icons, for Category 2 I want to see 25 icons and for Category 3 I want to see 15 icons.  I can't seem to get either visual to work this way.  This is a very common approach to pictographs so I'm sure I'm just missing something.  Any help would be much appreciated.