I hope I don't harp too much on this one note, but....
The very day I bought my two 6 volt batteries, my first stop was by the "golf cart business" -- I had a friend with me who is a golfer and he does regular business there. I knew nothing about "golf cart batteries" so I took him with me. When his friend at that business learned of my intended use, he suggested that I go on into town to his supplier. As I recall, I saved $10. per battery by following his advice.
His price includes the usual delivery and set-up at the golf course. He knew I needed none of that. I would handle the batteries and installation myself. And so it was.
It was this same battery supplier with whom I checked this past week when I needed a battery for my little solar installation. Two 6 volt batteries wired in series would have been better, but in this case 'overkill' and would have cost twice as much. But I have never regretted putting the 'golf cart' batteries in my Montana.