Last summer, I noticed a seedling with leaves that have extremely deep lateral sinuses. As deep as you can get, right down to the middle leaf vein. Is this a good trait? Well, the clusters hanging under these leaves would certainly receive more sunlight, a good thing in the north. Maybe you wouldn’t have to remove the basal leaves to get more light on them. Also, you would probably have better air flow through the leaf canopy than in a vine with more complete leaves. This might reduce the incidence of rots and mildews. However, given the reduced leaf area of these leaves, would you need more leaves per shoot to support adequate fruit ripening?