.030 difference in thickness between J frame and LCR? Holy crap, guys!! Why would anybody really care? the difference in thicknesses of holster materials more than makes up for the difference in "thickness"....
The real thing to consider is overall volumetric size, combined with weight.
In a gunfight, one's adrenalin causes a disregard of recoil, but, the muzzle flip that the recoil causes in a very light handgun can impact living or not due to time required for follow-up shots.
I'd much rather have a 15+ ounce .38 J frame (or even J magnum) than something that won't allow extremely quick follow-up shots.
Plus, with the requirement to practice, practice, practice with one's carry piece, the feather-weight revolvers are so unpleasant to shoot that most folks don't do the required range work or practice.
Just my opinion.....................