But, if you didn't know where to exit the cables, all you have to do is measure the width of your servo arm. If the servo arm is 3 inches wide, the cable will exit exactly where the fuselage is 3 inches wide.
Works great with parallel cables. Not so with crossed. My experience is that I've had to cross the cables in the 6 planes I've used pull-pull on. Not fond of cutting formers to prevent the cables from rubbing on them.