I owned a 43 .. good pistol.. traded it … After I traded it .. My G2c took its place … now a GX4 … I carry it with a extended 13rd extended mag …
I can't imagine there would be much concealment difference, not even if you wear your shirts as tight as my wife. I prefer 11 rounds over 7 (whatever, less) even in a "good area".
I would say the smaller one, but overall efficiency would depend on things like your build, holster used, and clothing worn.
One's build, holster choice, and clothing worn does make a difference. I am 5'9" and 145 pounds. While my G43 and Sig P938 are definitely easier to conceal, I can still conceal my full size Glocks and 1911s easily when I dress for what I am carrying. I usually carry at 3 o'clock with an IWB holster.