You should also move the exercises that hit your rear delts to the frount of your shoulder routine. Usually when a perticular bodypart is lagging it is because your not stimulating it to grow. One week out of the month I reverse my routine so by the time I am up to my big compound lifts I have pre exhaustion in the supporting muscles. This will obviously lower the weight you use for the lift but form and muscle contraction is more important than how much you are throwing up. So until you catch them up with the rest of your shoulder just start with any rear delt iso move. Form is of most importance because lack of control will bring your back into the movement thus cheating your delt out of the pump,imo.