Actually, it just boils down to what works best for you. Since you do not have experience with these yet, my recommendation would be to get at least one cartomizer in a low resistance, one in a standard resistance, and one in a high resistance. Try all three with your favorite flavor, and decide for yourself which one that you prefer. It's really the only way to know for sure.
With a cartomizer with lower resistance (less than 2.0 ohm), you will get more vapor and a warmer vapor. It also may be too warm or harsh for you, should you find out that you prefer a cooler vape. I happen to prefer a cooler vape, myself. I've tried the lower resistance cartomizers and dual coil cartomizers, and to me they produced a harsher vaping experience that I didn't particularly enjoy. Many of my flavors tasted burnt. Your results may vary from this. There are many vapors who prefer a warmer or even hotter vaping experience to more reproduce the experience of smoking an analog. That's just not for me.
I have tried all the resistances, and both single and dual coils. I was able to figure out which ones that I preferred by actually trying them out for myself. I'm not sure that I would let anyone tell me what is best for me, because they don't know my preferences. Being inexperienced with any of these, neither do you. So do yourself a favor and try both dual coil and single coil, and all three resistances.