setting up 4 100w panels going into a 30 amp renogy rover contoller. the four panels will be close to one another on a roof and are shaded vs sunlit together. I could do 2x2 series/parallel or just go series. I'm currently thinking it doesn't matter because both are the same power and the controller steps down to 12v in either case. I considered parallel briefly so I could start adding more panels (e.g., 2 groups of 3) but then I realized the controller can't handle more cells anyway (eg, 21v x 5 exceeds 30 amps x 12v). So growing would involve adding another controller anyway. Am I thinking about this right? or is there some advantage I'm not considering to a 2x2 setup instead of simply dropping 4 in series?