Candy Apples on Richeson

I've started working on another drawing of candy apples because I have to get several done for our colored pencil exhibit at the Wellesley, MA library in March. This time I'm trying a new surface, its Richeson Unison Premium Pastel Surface which is on gator foam and the color is terra cotta. The surface works beautifully with pencils, the pencils apply so evenly that I may not have to use mineral spirits to make them flow. I'm checking with the company to see if I'm able to use mineral spirits on this surface. Because its applied to gator foam, the surface seems to be a little more flexible than hardboard and the pencils feel better as they are applied. If that makes any sense!