What are your plans for the dual battery? How many and what kind of accessories will you run? The sPOD is the best platform for wiring. It can be used for a dual battery. If you get a Low Voltage Cutoff with your sPOD your starting power is still there, despite the drain. I would start with the sPOD and if you find your extras (fridge, etc) shutting down then I would get a 2nd battery.
Check out this little thread for opinions:
Considering a Dual Battery
RUBI / 37" Grappler's / 3.5 RK X / 5.38's
RockKrawler : PoisonSpyder : RCV :LOD : Iggee : sPOD : Nitto : WARN : Yukon : Rock Hard : Tatton : PolyPerformance