This video is informative on carb cycling: YouTube - MetroBoxTV's 5-Day Carb Cycling Plan
20% body fat is good for a female, it's in the high end range for athletes according to this chart:
Understanding Your Body Fat Percentage
You probably wouldn't even have to lose 10lbs of body fat to look ripped in a fitness model sense.
For males, if they want to see definition in their abs, apollo's belt, or "great toned legs" as the OP wants, males want to shoot for a body fat percentage below 10% depending on how toned they want them. He might want to do some squats, leg presses, lunges, hamstring curls, and calf raises too.
I believe that it's below 14% for females to get well defined abs.
sheds some light on carbohydrates.