As much as I like the feel of a 4 5/8" sing action, I've found that I shoot the 5 1/2" and 6 1/2" barreled guns much better. I think it's not just the sight radius, but the slightly longer barrel makes the gun balance just slightly barrel heavy which in my experience seems to help me shoot tighter groups. The 4 5/8" has a neutral balance.

Of all the 454's I've shot, my favorite was a 5 1/2" mdl 83 that was roundbutted and mangnaported.