You sound like a fucking narc... 420 friendly! lol Have some common sense. 99.9999% of these girls are slangin' dope or hooked on it, and their level of paranoia will only make them believe that you are either:

1) a fucking narc
2) a chainsaw rapist
3) a 6 foot giant rapist-narc

Get a clue, and make a simple ad. Buy a video camera and call it a porn shoot. Under-promise and over-deliver.
Keep it simple, and don't over-complicate the deal.