i like to use the smith machine n grip outside the line, that really helped the part that connects to the shoulder really grow, n then a regular grip and then behind the back,
then I move to the trap machine and load that sucker up, and then I move to the sissy Squat machine and load that baby up and shrug the shit out of my shoulders.
and tbh you really dont have to use a lot of weight a meduim amount and good form is sufficient to stimulate growth, just like any other muscle, lower it controlled and lift as high as u can controlled and they will grow.