For a simple dumb controller - as opposed to one that boosts or bucks the voltage to be just above that needed to push the current into the battery (MPPT)- you want the maximum power point voltage of your solar panel setup to be at or just a bit above that needed to shove all of that current they produce through your wiring into your battery. The controler you have is an excellent controller for its cost and what it does and that is why Mr. Hurd is at least a dozenair from selling them. There is no point of connecting your panels in series on your system with that controller though because you would reduce the current and add voltage you do not need.
On a side note, I have a couple of MPPT controllers in use and they are different animals. They make better use of the power of my panels, but they also have a lot more parts and relays and such and are a huge amount more expensive. I also have a bunch of non MPPT controllers in use, such as Trace C40's, some home brew that just open the circuit when the voltage gets too high and such. While the MPPT controllers get a very noticeable amount more power out of the panels, I suspect that the simpler controllers will outlast them by a long shot. I have wondered, but never actually calculated, given the life expectancy of panels, wiring, batteries and such, if it is economically worth the extra money for mppt versus using the difference to add more panels. Currently, my belief is for me that it is worth it in my case, but this is largely because I am in an urban area where space is limited and so getting extra power out of that space has an added value. Rich