You said you would be installing a period correct pad...I'm not sure a soft black pad was available in 1925. There are soft red, orange, brown and black pads available that would be appropriate....NECG offers some nice pads that when fitted up right look good and age/vintage appropriate. You can get some pad base plates to bend without cracking them (usually by warming them up and slowly bending), it depends how much curve you are dealing with though.
A rasp would be a good place to start when it comes to removing the cheek piece.
