Chuck Hawks has some great articles. The best point in this article is that
a heavier weight gun is better for helping to absorb recoil, so stay away from the lightweight metals and the polymers.
Massad Ayoob has a GREAT tip for women who want to rack the slide on an automatic:
Armed and Female by Massad Ayoob Issue #63
Now, let’s look at techniques. The average woman’s fingers will be shorter by about a digit’s length than the average man’s. She will have less upper body mass and strength than her brother. Thus, some shooting techniques may work better for her than for him, or vice versa. For example, most men operate a semiautomatic pistol by holding the frame in their dominant hand, and reaching across their chest with the free hand and grabbing the slide to “rack” it back. This is an upper body strength intensive technique, pitting arm against arm, and a lot of smaller or older women can’t do it well with many pistols. They’ll have better luck with the “SLINGSHOT” technique, in which the support hand firmly grabs the slide and pulls back while the gun-hand is pushing forward. This can be combined with a turn of the hips that puts the entire body weight into the movement, making it happen almost effortlessly.
I use this method because it is functionally easier--not because I can't do it the "traditional way." [Let me know if you need more info on this slide racking method]
I agree that you should take your wife to the range to test fire guns, but bear in mind that the recoil springs of a rental are typically well-used so less springy.
I once read in the forums that a man hand cycled his new guns at least a 100 times to break in the springs, make sure the slide functions smoothly, and work on muscle memory of how to grasp the slide and rack it. I think it is a great idea....
Best of luck in finding a suitable gun for your loved one,