You may have jumped into the middle of pool, when you could have started in the shallow end.
The Witness Limited is a pricier version of the standard Witness large frame gun. There are other options that might also be better, and less expensive.
The Witness is an almost "clone"/close copy of the the CZ line, and they all feel about the same in you hand.
(Witness stopped importing their small-frame guns, recently, and everything is now the large frame, but many, many of the other, smaller models are available, both new and used. Converting any of them to SA only is simple and relatively inexpensive... but I wouldn't bother.)
That's because all of the CZ clones that don't have decockers (Witnesses, Tanfoglios, Baby Eagles, line and CZs, too) are SA/DA: they can be carried and started in SA mode.
My point: there's no real reason to buy a SA only version just to get a gun that can function as a SA gun. Unless you get a decocker model, all of the CZs and CZ "clones" do that and can be carried cocke-and-locked.
Before committing to the Witness Limited, I'd recommend that you also look at the 75B, the 75B Single Action, or the 85 Combat (which comes with an adjustable trigger and ambidextrous controls).
Or look at one smaller frame Witnesses. That smaller frame Witnesses or smaller-frame CZs (75s/85s) are all going to feel very much like the Limited model, but because they're smaller, are even more likely to fit your wife's hand better.