If I was going dual battery I would go with 2 Odyssey Group 34's or 2 Northstar Group 27's. The Northstar will give you a slight uptick in cold cranking amps, reserve capacity, and ampere hours, but with additional weight compared to the Odyssey. The Odyssey's work well too and I run only one Group 34 at this time and it works great for my application. Both batteries I mentioned are AGM and if you are running lots of accessories I would definitely consider AGM batteries for that purpose. I don't think you can go wrong with either that I mentioned, but you definitely have to pay to play the AGM game for sure. They will hold up great (in my experience) and with a dual setup you shouldnt have any problem running most anything you throw at it. Hope this helps!