Depending on your traffic (and the quality, content and updates inside Amateur Pages), you should get over 60% of trials converting to monthly memberships. I don't know how well Amateur Pages retains its members, but I think 3-4 months is about the average for most large paysites.
Also, I would recommend the partnership program over the per click program as payments are done by a third party (Ibill is money in the bank).
Just my
