Affiliates with offline payment

Hi,

Is it possible to use affiliates without the automatic payment. For example, I'd like to be able to see that UserA has referred 5 friends this month and then I send him a gift voucher. I'd then want to be able to mark those 5 referrals as 'paid' so that I don't count them again.

Is that doable?

Also, does the link take them to the homepage of the site or the Membership registration page? I want to use a custom registration page created through gravity forms.

Thanks