I remember a time when it wasn't uncommon to hear that competition shooters used their full-size revolvers and pistols for competition, but carried snub nose revolvers away from the range.
I remember not too long ago when you could talk to LE firearms instructors and find that while they liked their hi-cap duty weapons while working, the snub nose revolver was the most commonly carried off-duty weapon?
The common response to asking an experienced LE instructor why "just" a snub? Because it was considered generally adequate against potentially encountering 1 or 2 attackers while off-duty.
What's changed?
Now, OP ...
If you can't experience consistently good accuracy when shooting your J-frame, and you're unable to consistently obtain a firm and solid grasp of the little Shield because of the size of your hands?
Well, maybe you need to look at something other than a J-frame or a Shield.
Or, maybe you need to get some training and learn how to shoot the snub better. Or go ahead and try the different holster (but that won't change the size of the grip frame).
While there are times when I'll still belt on one of my larger guns for retirement CCW, more often than not I still prefer to pocket holster one of my J-frames. I invested some years of the range time I worked as a LE firearms instructor in running my snubs in training conditions and drills. Whether it was the typical 3-11yd, 3-15yd or 3-25yd courses-of-fire (depending on the courses being used at the time), or just checking my basics by shooting paper or steel silhouettes out to 35-50yds with my DA/DAO snubs, I worked to maintain skill with them.
If I can't fit a snub into the short and tight front pocket of some particular jeans? Well, that's why I eventually picked up a couple of LCP's. They saw range and qual time in the same drills and qual courses as the snubs saw.
The main difference,
for me, is that while I found the LCP .380's were a bit more difficult to run out at 35+yds. Then again, I don't carry one of the LCP's expecting to ever use one to try and engage an active shooter at longer distances.
Capacity is fine, if that's a concern. It's not so much of one
to me.
If you can't get a good grasp/grip on the gun, though, or you can't get consistently good accuracy, it might be the gun/shooter "interface", or it might be the shooter's skill. Figure out
what needs to be addressed and how to best address and resolve it.
Just some thoughts.