I'm finally getting ready to make my own leaders. The book says 4 inch, 18 inch & 24 inch. I have four rails, does this sound right. Do I only put leaders on 3 of the rails. I bought 6 yards of duck cloth. I was just going to slit it down the middle & put 22 inch on each. Of course I can't do that cause I'm short about 18 inches. The 4 inch one sounds too short.