It's hard to come up with patter for someone else.
For example, what is the rest of your show about? How are you hoping to tie it in with the rest of your show? Find some kind of common thread between the Stratosphere, and the trick you perform BEFORE it, and then it will be easier to develop the patter.
RIGHT ON Kristen! Also who or what is your character? i.e. Is your character a wizard like Harry Potter, is he a medicine show performer, does he try to be Houdini? Each character has it's own patter. My patter is totally different when I am Paddy The Clown than when I am Professor Paddy. Both character perform the exact same effects, however it is a totally different show for each character.