I see what your saying. Your right about sticking the first then, you would have 4ft to make up any difference. Just makes sure your heel heighth at the plate is the same, and your height 20ft in is correct and have the rest built. We home built trusses for my folks's 40'x50' garage and it took forever. I always do whatever it takes to order them for my jobs. They have really come along ways with what they can do with truss systems.