I do belive in periodization as well. Surprising enough only 1 heavy working set works best for my gains. Really the only time I do more than 1 working set is early in the training cycleI also never do more than 5 reps if I am training for strength, which is always what I am doing in the deadlift. I may do 5 or more sets on deadlift day. I deadlift every other saturday and squat every tuesday. Both to to build my dead. As was mentioned earlier, you are only as strong as your weakest portion of the lift.
So I would figure out what that is and fix it. It took me 4 attempts to finally pull my first 600 at a meet.I swear I was about ready to just bag it. The problem was I wasnt training my weakness, just my strengths harder thinking it would come around. Turns out my hamstrings were the culprit and once they caught up to my back strength, everything clicked.If you ever want to talk training feel free to pm me.