I want to try coloring soaps and doing different swirls, but I want to leave some of my soap the natural white/off white color. The fragrance I want to use makes the soap turn darker. So do I calculate the fragrance/essential oil amounts based on the pounds of oils I used in the whole soap or just the pounds of oils I plan to add it to? I only want to add the scent to the darker colors so my off white colors don't darken. I don't want to add too little and not have it smell strong enough, but I don't want to add to much to part of the soap if that's not good either. Does that make sense?