John- The Boston B&C has a few major differences from others. The raked back claw is the most obvious and easiest to do.
In addition, the claws are quite thin with knobby knuckles and they come up very high on the ball so that the three last knuckles form a small triangle just below the point where they leave the ankle, leaving very little web at the top of the bal.
Also, the ball is quite chopped off at the bottom and many of the "circles" where the ball hits the floor are more like rounded off squares.
As a disclaimer, these attributes are found on the Boston feet that I like...............there are many types of "Boston" feet that are nothing like the one I just described.-Al