Moderate weight or moderate sets? Use more reps per set, or use heavier weight, more sets, and fewer reps per set? God almighty, which is the optimal way to train for size?
If you're a true musclehead like I am, you've probably read (or heard) a lot about periodization, either from classic textbooks by East-European sports training and weightlifting authorities (including the classic texts by Tudor Bompa), or by researching the subject online.