Howdy from South Carolina, and welcome to the forum.

You say she "handled" guns, but has she shot them?

As a woman, I know that we tend to gravitate to petite handguns, until we fire them. We never consider that less gun mass means our hands are left to absorb the recoil. Do both of you a favor, and visit a range to rent some different sized guns. For a weapon your not carrying, mass is your friend, and you will enjoy shooting it more. You want your wife to be willing to practice enough to be proficient.

You eliminate other choices because of "size in hand". But were you aware that replacing grips is easily and often done. The 3" and smaller 686 has a round grip frame which accommodates smaller grip profiles. These are three 686's. The left is a stock round grip, the middle is a smaller than stock round grip (Hogue Bantam), the right is a stock square grip.