I would recommend you to reach LoyceV
I'll only consider advertising a casino if it fits these requirements:
since 2 days ago, the Netherlands no longer allows advertising for gambling sites (including affilates), unless they can prove less than 5% of the players are under 24 years old.
You could try PM them directly while mentioning the details.
Unless the user has a thread in which he offers his signature space, you risk getting banned if someone reports the PM:
29. Sending unsolicited PMs, including but not limited to advertising and flood, is not allowed.
Do we need to run a campaign or can we hire these users without a campaign?
Bitcointalk's mission is "to be as free as possible", so within the forum rules (click the quote above), you can do what you want.