How do you select a substitute material in Moldflow?

Sometimes I need to select a substitute material in Moldflow.
 
Getting your material characterized will typically provide the most accurate simulation results. We also offer data fitting software if you would like to input your own material data. Even then, we sometimes need to select a substitute material.
 
I would first search by the Material family, Filler type, and loading (if applicable), and I add a Search Criteria to only provide Gold Warpage materials. This is optional but helps ensure good material testing since a material that is Gold for Warpage; it’s Filling and Packing data must also be Gold as well.
 
Once I have my search list, I add a Column for Moldflow Viscosity Index. The values in parenthesis are the test temperature in degrees C and the 4-digit value at the end is the viscosity value. I would select 2-3 materials at varying viscosities simply to compare pressures between low, medium, and high viscosity materials.
 
Do you use substitute materials and if so, how do you select them?