Yes that is what I used. The thickness/temperature rating relation is a strange one. For a given insulation material thicker is better but you can't use thickness when comparing across types of insulation.

For instance a lot of people are familiar with how much loft of down it takes to get to a certain temperature rating and they can't believe synthetic can do it with less loft because they know that down is a better insulator. What they are missing is that down is better PER OUNCE, not PER INCH of loft. Synthetics are warmer for a given loft but they are heavier. So a thin synthetic quilt can be quite warm but it will weigh more than a similar down quilt that is loftier and has the same temperature rating..