I've been shooting various styles of firearms since I was a little girl. I listen to my husband better than anyone else on Earth. He still knows better than to buy a pistol for me unless I've tried it out myself. Finding the most comfortable combination of pistol, grip, & ammo will be most expedient if she takes up with some local ladies after a match for show & tell & shoot. Ask ahead of time and most people will come prepared with various things for her to try out in addition to their regular match guns. I've seen felt recoil & long guns not cut to size run off more ladies than any other equipment issues, so be prepared to not only buy what is comfortable for her, but also to finesse things as she goes. I guarantee you there will be ladies happy to share their experiences with her and help her try things out with no pressure. My main match cowboy pistols are Ruger Bisley Vaqueros in 38 spl with 125 gn TC bullets. I have small hands, but these were and still are the most comfortable for me to shoot two handed. We reload ammo, so that helps, too. When I shoot black powder it's even more comfortable...and funner. More than anything, enjoy spending time together in an exciting hobby!
For reference, I've been shooting a Stoeger with double triggers for around 7 years and absolutely love it. My arms are not terribly long, so in addition to things like reasonable loads, a bit of finessing of certain mechanical aspects of the gun, pulling the butt plate firmly into the shoulder pocket, and so forth, we measured my length of pull and had the stock cut down to fit my body. I cannot overstate how much difference this made in my ability to not only shoulder the firearm, but also to rapidly load, trigger, shuck, repeat. Also, be aware of how much finger is in the trigger. I don't have much more than the tips of my fingers on the triggers. Oh, yeah, notice I said fingerS and triggerS. From the time I pick up my shotgun until I ground it, my index & middle fingers are in their respective places within the trigger guard. I shuck over my shoulder with a quick jerk of my right hand while grabbing more shells, so, the firearm never leaves my shoulder. What I'm saying, is you do you. Find what works with the help of experienced competitors, then practice until it feels natural.