Don't want to give anything away, but you cannot use a borrowed deck. I'm a fan of organic tricks.
Even if you have to add a duplicate card to a regular deck, that's cool, although I prefer tricks
that rely on purely on slight of hand, misdirection, etc.
What others have said about the
PBR is true - it's critical to making this trick work right. I may try that portion of it, leaving
out the method using the deck.
Also - the explanation leaves out a critical piece of
instruction regarding the deck itself. That really ought to be part of the cost.