Why are you limiting a vast field to a mere (2) options?
If the tray can accept a 13" battery then it can accept a group 31 battery. If the tray can accept a pair of group 24 or 27 batteries then it can accept a pair of group 31 batteries.
Some people screech at the thought of spending money for a pair of AGM batteries then purchase 1500 dollars worth of tires while whistling dixie. And I can promise adequately cared for AGM batteries will live to see the grandkids of those tires. Unless of course the RV owner is convinced driving 100 miles on a vacation is considered long-distance.
But choosing AGM batteries by price alone is a real loser. I choose my new purchases using overwhelming mass positive reviews.
It seems like the cost of gasoline and the cost of batteries brings out a form of financial blindness or ignorance. (anyone who does not buy the very cheapest must be stupid). I don't buy plastic covered reclaimed foam over pine furniture, melmac dishes, and K-Mart blue light linens for a reason and it has nothing to do with snobbery.
If I have had agonizing short lifespan history with a certain tool I figure ten returns to a Lifetime Warranty vendor is more than a little challenge to my intelligence. So I choose Snap-On, MAC or Wiha. I purchased a pair of Wiha's eighteen dollar ALTERNATIVE BRAND flush cut diagonal pliers -- STUPID MOVE! In less than a year the tips, that top 30% of of them have SPREAD. Close the pliers and there is a .010" gap. For a mere ELEVEN DOLLARS postage Wiha will send me another pair of garbage dykes. The Second time Stupid is not my bag. I will spend the thirty dollars and end up with a good tool. Fifteen dollars down the *******. And I am screwed for flush cut pliers. This is intelligent?
Cutting OFC to 18 AWG should not have challenged the lifespan of the pliers. But my "saving" fifteen dollars makes me look like a *****'s ***