Iron Air,
The trigger stop will reduce the amount of trigger overtravel after the sear break, thereby theoretically reducing the amount of movement of the gun while the bullet is still in the barrel, thus contributing, again in theory, to being better able to hit what you're aiming at. With accomplished .22 target shooters, as well as DA shooters ( not simply shooters of DA guns), the results can be readily seen. As I said, the Redhawk needs one, in my opinion. However, the stop MUST be properly adjusted. For me, this means allowing just a bit of overtravel, rather than having the back of the trigger contact the stop immediately after the sear breaks loose, which I find can be jarring to the sight picture and movement of the gun, not to mention being at risk for screw movement which could prevent the gun from firing.
Yes, the design requires a heavy trigger pull in a Redhawk to assure dependable ignition. This requirement is heightened if you shoot it DA with magnum primers. About the best you can do is stone the creep out for SA shooting, then simply work with it enough to learn to shoot it well. Spring clipping and replacement can work, but can put you in danger of likely ignition problems.
Relative accuracy of FA's related to caliber? Scoped, with me shooting, my 353 (.357) is often a 1 MOA gun; the 757 (.41) can be a 2 MOA gun; the 252 (.22LR) with a trigger stop,maybe 3 MOA; the .475's 3 to 4 MOA, as is the .44. (also with a trigger stop) My .454 and .50AE/.500WE, maybe 4 to 5MOA. The 97's are similar, with the likely champ being a .32 Mag. It's not scoped, so I can't be sure. How much variation from caliber to caliber is the gun.. the caliber...the load.. my recoil tolerance ? I dunno. Don't much care. They are good enough to suit me for their intended use. Trajectory will be a more critical factor than these differences in pure accuracy to hitting, at distances between say 35 and 125 yards in a hunting scenario, or even beyond, in target shooting.