Like Bmorgil and 56willys have said, the dimensions for the battery tray can be closely matched to the CCAs you would like to run. As you said, you don't need a whole lot for your region you operate. A group 24F is great for no extra accessories like a winch or a bunch of lights. 56willys runs a Wally World special, and that makes it real convenient if you need a replacement, especially when they were open 24 hrs. a day. I still run a 6 volt, but my local Wally World had one on the shelf.