I think two 12 volts wired in series may be the way to go since they are more popular, less expensive and readily available if you get in a pinch and need to replace them..
Make sure you get true deep cycle ones since many are labeled marine or RV but are not true deep cycles...
Look for ones that are used in golf carts like this
https://www.amazon.com/Trojan-T-1275...7117025&sr=8-8
If you have a few extra $$ laying around you could go with Lithium Ion. They are lighter, charge much faster than lead acid or AGM and can be drained down to 0% without harming the batteries. With AGM or Lead acid you should not drain down below 50% so you really only get half the advertised amp hours. The only draw backs are these batteries don't like extreme cold so they should be stored indoors over the winter and you need a battery charger that supports the Lithium Ion charging profile.
