Very good OP, thank you!
Having one (3") I.m very impressed with how well it shoots and handles the 9MM case in extraction mode.
As far as the trigger pull when I first got the gun I vacillate a lot about the trigger pull. Do not remember my exact words but I said something like Superman used less finger pressure squeezing coal into diamonds than my 547 need in double action mode. Almost did not get it due to that pull. I shoot revolvers mostly DA.
This was the first one I saw for sale in my area after looking for about 5 years so I figure stiff trigger pull or not I best get it.
I would rate the gun at a easy +90.
After I got it I was going to do a action job, but did a lot of homework and understood about the limit pin and the need to set off anything that was in the chamber. No spring work done just a little gentle stoning and the pull improved a bit.
It shoots well and IMHO recoil feels better in that gun than the same load in a Semi Auto. Hey that's me your results might be different.