You can, as others have said and as you know, increase your total annual harvest with fine-tuning the angle of the array(s) during the seasons. I used to, at first. Then, I did some testing and found that, for my uses, setting the angle at the worst month [January here] for solar [daylength, etc.] was fine. I no longer bother to change the angle. So, it kind of depends on how much you want to work with it. Keep some written records during the course of a year and it'll help you decide.