Do an energy audit, best done with a battery monitor to determine your needs. Your batteries are NOT deep cycle regardless of what they say on the label. Marine deep cycle batteries are a compromised starting battery.
You might want to plan for 2x 6V GCs deep cycle batteries which will give you 230Ah, ie 115Ah to 50% discharge. Your present batteries are about 160Ah. 2 GCs would be wired in series. GCs are also heavier and taller.
Inverters can draw a lot of power. For 1A AC they draw 11A DC or 11Ah.
What does this mean? Aren't your current batteries wired in parallel?
"I currently have 2 group 24 deep cycle batteries. My understanding is that group 27 are better fo the application, but for now I'm working with what I've got on hand. I'm looking to wire them in parallel to boost the amp hours."