if Im right your still a beginner right? If so then you dont need all this "variation" and switching stuff up, make/find a routine that you enjoy and has the heavy pressing, squatting and deadlifting in, mixed in with some assistance stuff. Some good assistance exercises are bent over BB rows, incline presses, RDL's, ab work and chins.
Here are some of the good routines that I can think off from the top of my head:
Super Squats 20 Rep Squat Routine
5x5 Calculator
http://www.elitefitness.com/forum/weight-training-weight-lifting/ultimate-training-split-650464.html
http://www.elitefitness.com/forum/weight-training-weight-lifting/listen-up-n00bs-670495.html
IMO if your doing a several of the following exercises then you dont need anything else for shoulders as a beginner: flat BB Bench press, Incline Press, Standing BB OHP, Seated DB or BB OHP, Dips, Bent Over BB Rows, Deads.
If Im wrong and your not a beginner and you have found that after a year or more's worth of consistent training that this style of variation works then year laterals would be ahrd to do 2-4 reps maybe change them up to 6 reps. That would be the first thing I thought of...
That's what I call the perfect answer!