You seem pretty hung up on a few arguable points that are pretty subjective.
I'd like to respond to a few of them
My experiences with an sp101, as stated, is mostly with handloaded 158 grain jacketed rounds loaded with enough H110 to get it trucking at 1150fps average out of a 3" barrel.
1150 fps with 158 gr is a modest velocity for 357 and probably an okay choice for the SP101.
1150fps out of a 3" barrel is most decidedly not a modest velocity for a .357 magnum with 158 grain jacketed bullets. That is actually pretty close to max book loads, and meets or exceeds most full house factory ammunition of the same caliber and weight.
As stated by myself and others, recoil is smart out of an sp101, but with the hogue grips it is a brisk but not particularly painful recoil.
"probably okay"...why wouldn't they be? They are within spec and under max charge.
re the SP101 over others
There are more grip options and especially holster options for Smith & Wessons.
There are probably more grips overall being made for the Smith by more manufacturers, but the Ruger has the upper hand when it comes to actual options.
The ruger has a post grip frame, whereupon the Smith has a full grip frame. Therefore the Smith is confined to grip profiles that must accommodate the profile of the grip frame. The Ruger is much more accommodating of different profiles of grips.
Ruger
J frame Smith
You can see there is much more room to sculpt the grip into various shapes and sizes with the Ruger grip. It also puts more of the guns weight over the barrel, which adds to the improved recoil of the Ruger.
The lightweights make better shooters if confining ammo to 38 Special. Even the SP101 was introduced as 38 Special only. The versatility to shoot 357 Magnum is mostly in theory for many owners, who find the guns simply too small for magnums.
The versatility of being able to shoot .357 magnum must be of value, since the .357 magnum Ruger still enjoys brisk sales as compared to the .38 version. I am a fan of the free market, and the free market likes .357's in small revolvers. The Ruger was introduced as a 38 special because it was designed with a smaller frame window...then the free market spoke, and Ruger quickly redesigned the frame window for a longer cylinder.....and subsequently sold the snot out of the magnums as compared to the 38's
I myself fire more .357 out of mine than I do .38.
Having both guns, I am not prepared to accept that the only slightly heavier Ruger can shoot stouter ammo with much of an improvement in shooter experience.
I don't know what to tell you, There is a saying...Your mileage may vary.
In this case my experiences differ significantly from yours.
What seemed the priority was smaller size and weight for an Asian couple of smaller stature.
This is actually a mistake I see many smaller people who are inexperience make. Thinking that a smaller, lighter gun will be better....which is directly opposed to the laws of physics. Smaller and lighter means more transferred/felt recoil. Remember, this is primarily a nightstand gun. Lightest weight is not really a priority as I'm interpreting the OP.
What is a priority, is a comfortable grip and enough heft to soak up some of that recoil.
Both the Ruger and Smith are pretty much a wash in grip options, with each being offered in suitable grips to do the job...I myself am a big fan of the Hogues for either.
However, the Ruger can accommodate small hands just as easily if not easier than the Smith, and is heavier enough to noticeably diminish felt recoil, without being too heavy for comfortable carry if needed.
You said as much yourself...
It needs mass and barrel length to be controllable, especially for this person of smaller stature. What seems to be missing is empathy for what others might need or conclude.
It has nothing to do with empathy. I just don't accept that your reasoning is universally applicable and should be the default.
I've fired plenty of .357 magnum out of a few small framed steel revolvers, and don't find the experience with the sp101 to be as you describe it. As always, mileage may vary.