Pretty sure Mike Beliveau (Duelist Den) cut a 2nd V-Notch sight into one of his Colt revolver hammers. Possibly a Dragoon or Walker.
You might dig through his videos on youtube / here:
https://www.mikebeliveau.com/I also would try 30gr.
Usually a lower powder charge will = tighter groups.
However, I too like to see how much black powder I can cram into a BP revolver chamber and stuff a deformed ball on top with no lube or wad.
For my Pietta 1860 Army, that is 38 to 40gr of FFFFg - yes you read that right 4F.
For my Pietta 1851 Navy, 30gr of FFFFg.
I would think you can stuff more than 40gr into a Dragoon but I don't own a Dragoon or Walker.
Old pic but a pretty good group with my Pietta 1860 Army:
Attached FileGroup was shot with 2 hands at 21ft using a 6 o'clock hold at the bottom of the target. Powder was Graf's Schuetzen FFFg. Load was 30gr with Bore Butter lube on top of a felt wad, under the Hornady .454 round ball.
My best accuracy has always come from loading powder, felt wad, lube, and then ball. It is a tedious loading procedure.
If I'm just shooting for fun I will shoot powder, ball, lube then alternate powder, ball, and no lube.