My friend who did it also had small hands (or as he said, short fingers) he got an aftermarket bird's head grip frame, and had to cut it to fit the Bisley hammer he wanted.
For him, enlarging the opening in the grip frame was easier than grinding down the Bisley hammer. No other parts were changed or used, and the gun worked fine.
I thought he was off his rocker, but he liked it, up until he discovered it was painful to shoot when he got up to about 3/4 full house .44 Mag loads...
(which I warned him about but don't listen to me,,,noo...
)
Should be no trouble at all in your .357, once you get it fitted.