You've just got to look at their contour charts and compare them for yourself, they're all different. For example, a Bartlein #3 is bigger than a Rock Creek #4. You just have to compare them and see what's what. Don't feel the need to be limited to their contour chart either, most makers can duplicate factory or other contours if you want. If you like the contour on your CDL then tell them to duplicate it.
