From what I have been reading about the Bisley revolvers and matches is that the grip angle/design was for better wrist posture and recoil absorbtion. The (Colt) Bisley grip tended to force the point of aim downward if used straight arm. This is because they were designed for the Duelist bent arm style stance. The rear notch/front blade aligned when the arm bent.
The competitors used target ammunition, however changed to a more powerful charge when switching from the 20yd target to the 50yd target. These targets were timed, and only visible for that amount of time.
The original Colt Bisley grip is far different than the Italian clones, the USFA replicas and especially the Ruger style which was a compromise of modern and vintage to appeal to American shooters.
Apparently SASS and CAS has a "Duelist" match where the Bisley grip is preferred. I'm not too familiar with SASS but have always been interested. I've watched some of it in person and video.
I have a bit of time on my hands due to being on a medical LOA...this research is keeping me entertained and "out of trouble" as my Wife says..my back/left side is a mess and cabin fever is setting in....Neighbor had two large oaks come down on his property. I was thinking of a way to help, I have several chainsaws. I was thinking of getting them out, prepped and running to offer to him and whoever is going to help him. Same with my 4 wheelers. Somehow my Wife knew what I was thinking and I got a stern look and a "YOU ARE NOT HELPING HIM CUT THOSE TREES".......sheesh all I was going to do was offer equipment.....and maybe a cut or two (once she was at work lol), I love cutting trees. Not so much the limbing and dragging, but bucking big trees to me was always a blast.