I see more and more people talking about AGM batteries, in the earlier days they were priced quite a bit higher than now. Do most people going from the T-105 6 volts just go to a 6 volt AGM or is there a higher capacity 12 volt AGM that makes it worth while to just go to four AGM twelves, close to getting rid of my Norcold fire starter and trying to get the most bang in the room provided--thanks