Solar

OK, I am ready to install my system which will be 2 255W panels, 45a MPPT controller, I have 2 12v 80 ah batteries which are new and will be replaced in the future with AGM's. The only thing I haven't finalized is series or parallel. I know this is opening the can of worms again, I have read lots of strings on it but still not sure. So let the game begin. Thanks for the help.