How can a firearm that has larger capacity be easier to conceal? Also, what does more or less accurate mean? Self defense is more about minute of man than quarter size groups. There is some important data missing. I am assuming that both firearms are chambered in a self defense caliber. I am assuming that both firearms have equal reliability.
Anyway, given these very generic choices, firearm B due to higher accuracy. It is better to hit once or twice with a lower capacity firearm than to miss a lot with a higher capacity firearm. However, knowing how and why many people make their decisions on carry guns, probably neither gun.