I went with a pair of AGM 6 volts from Amstron on sale from atbat.com
Great battery, great price.
Actually thinking about getting two more for a total of four to enhance our dry camping ability.
I would recommend spending the extra money on the AGM technology whatever brand you get. Trojan also makes AGM...
https://www.atbatt.com/amstron-ap-gc...cycle-battery/
Below is a simple graphic showing the correct wiring of (4) 6 volt batteries in a series/parallel configuration.