I was told by S&W last fall that the new 5" 63, a SS J-frame 8-shooter, I had bought could not be as slick or light as my tricked 617. Further, their 'trigger job' for the rimfires was only $85 as a result of their not changing the hammer spring, just easing the innards. I elected to go lighter with the 63's coil spring and polish the side surfaces - great improvement. Still no tricked out 617, but far better than it was - and better, too, than a box-stock 617.
I mention the 63 because S&W has a 3" 63 with HiViz sights due out by April or so - it may just be a lot better than a similar size 3" 317, DA wise. Okay, the 317 weighs 12 oz - the 63 will likely be twice that - maybe more. Pricewise, it should be ~$20 more, too, than the 3" 317.
I still think that a 642 - or a 442 - would make a great revolver. Larger grips may make it more comfortable - have her test the fit of a Crimson Laser equipped model - with a larger grip. If it fits well, all you have to do is find a mild round - like a 148gr full wadcutter - normally, a target round - but great protection for the recoil sensitive. Easy to find plinkers, too - the wadcutters are a little hard to find.
Good luck!
Stainz