Thanks for the info. I think a bobbed spur is my only option. I wanted the hammerless DA only for one less moving part.
It's funny (for me), when she shoots my M&P 9mm the brass come back at her head. Takes the fun away. I want her to get used to shooting, and have her own handgun that is just a point and shoot.
As just said by another member, the parts count is the same, DAO or not. When the sixgun is shot DA, the single-action sear part of the trigger never reaches the single-action notch on the hammer; simple as that. By not manually cocking the hammer, the SA surfaces do not meet.
Ruger does, indeed, make 4.2" GP100 and SP101 revolvers. Pick the one best-suited for your wife's hands, and it is BETTER to let HER make that decision, to ensure domestic tranquility. Women who have handled my SP101 and GP100 revolvers have tended to like the SP101.
Another factor in favor of the SP101 is that the hammer spur is quite small. I have both spurless and spurred hammers in my several SP101 five-guns, and have noticed that the spur is so unobtrusive, it never seems to get caught on anything, anyway, and I do carry mine often, sometimes two or three at the same time. Simply using a small stone to take away the sharp edges is plenty enough to make the SP101 spur easy to live with.
Notably, it is better to cherry-pick from among several samples of the same model, as some Rugers have quite smooth triggers when new. I am not sure how many gunsmiths are working north of the border.