You must do what you think is right, within safety bounds, of course. My buddy Ken shoots feral hogs with HIS ROA - with 35gr of 3Fg and a nose-hardened 230gr conical.
Italian BP manufacturers are renowned for recommending low charges on a just-in-case basis, the same as modern versions of many military calibres are substantially down-loaded in the interests of 'safety' in case somebody loads up an old clunker and get the bolt through his eye.
One such example of this is the PPU version of Swiss GP11, which is around 200 - 220 fps slower than the real GP11.
I think you'd agree that there is a very substantial difference between the 'recommended' load of 12gr, and the advice not to exceed 35gr - almost tree times the recommended load. Or maybe not.
Let me post you the NRA/N-SSA accepted figures, based on historical usage, for BP handguns.
.44 Colt Dragoon - .453 ball - 40gr 3Fg
.44 Colt and Remington Army - .453 ball - 28g 3Fg
.44 modern manufacture Remington and Colt revolver - .451 ball - 28gr 3Fg
.44 modern manufacture Colt Dragoon - .451 ball - 40gr 3Fg
.36 modern manufacture Remington and Colt revolver - .376 ball - 22gr 3Fg
.36 cal Colt, Remington Navy, Whitney, Pettingill, Savage, Cooper, Bacon and most other .36cal revolvers - .376 ball - 22gr 3Fg.
I also have a list of 60 proof loads used by manufacturers of BP arms if you are interested.