Already been done. The Diehard Platinum was their pick. The DH Platinum was just a white-labeled Odyssey PC2150, which is what I'm running. The DH is no longer made so if you want a great battery, you have to shell out for the Odyssey.
Chris, the Odyssey line is well regarded and well proven, not attacking it, so no need to defend it. But I don't think Overland Journal compared the option of using two 6V batteries in Series next to one Group 31 12V. That is what you referenced when you said "
I'll put my single battery up against your twin 6V systems any day." Just thought that would make a good article.
There is more than one 'right' way to do things sometimes. And many wrong ways as well. I'm not saying your way or my way is right and/or the other wrong, just presenting options..