For me the Philly defense is your normal guard... If your legs are on distance greater than the sholders and you keep your weight on the bag leg (the basic boxing stance) your front sholder will rise automatically. Drop the hand down and lean a bit furder and you are in the position that James is rolling in. From this postion you can do everything. You can step with your jab you can throw right hands, you will be able to step, this means that you will be able to control the distance and so on... The second step is to play with the distance. Bate him in by staing forward and when he throws his shots roll back and make his shots fall short.