Hi John,
Here is my take on it.
Firstly, everyone hands are different sizes, so opposed to recommending a particular model, it is better for them to see what fits best in their hand.
Also, everyone physique is different, so what may be good for me, may not be good for them. They could be left handed and I am right handed, and my handgun could not have ambi controls on it.
The best way to see what’s best for them, is to buy a blue gun for the handgun they want and run a normal 2 week body contour test, wearing the same clothes that they would do, as well as doing what they would normally do work wise. That way they can determine whether the magazine remains in their gun and their hip bone does not depress the magazine safety. Obviously this is not an issue for a heel release magazine pistol’s and revolvers, but should be done nevertheless, to determine the comfort factor.
John, you also assume everything is constant, that they will be in the same terrain, will maintain their handgun to the same standard, shoot the same brands, and reload to the same level of precision that you do.
How many people buy handguns for self defence, load the magazine and put it in the drawer fully loaded. Every magazine spring needs to “rest”, you cannot expect to function 4 or so years later kept fully loaded..
I, rotate loaded to rest every week, record in my shooting book how many rounds fired, if malfunctions, what type and with which magazine. That way you will quickly determine if there is an issue with your magazine on the range than when your life depends on it.
I have wasted so much money in the past buying the wrong guns for me, if only I wise wiser then. Like you say, it is a can fo worms topic