I would have to see your recipe, but with the grains you would be fine use ing the light. The dark DME will make a a darker beer with those grains. The dark DME also has, from what I have read, more non fermentables in it. I always use light or exstra light or pale DME . I let my Grain bill set my color. But do it how you want thats the awsomeness of brewing do it your way.