Medusa sounds like a fiesty girl! I have a scardy snake too, though he's not a BP, and Jo's had lots of great advice for handling him. Basically taking things slow but being firm and confident. The jumpier you are, they can sense that and get more jumpy too.

I'm not sure if they get used to fast movements. So far all my snakes have been pretty consistant in their reactions, either fine with it or nervous from the get go. Gomez always hides his head if we move too fast, so we always move slowly and gently with him and he relaxes. Hope that helps!