I'm trying to make an affiliate program for shared, vps,dedicated and colocation services.
Here are my questions, I'll be happy if someone could help me with them
1. Should the sum of payment depend on the the type of the services sold to make it appealing for affiliates and profitable for me?
2. Should the sum of payment depend on the amount of clients brought be an affiliate?
3. What would be more appealing for affiliates to for one-time pay-out or monthly payouts?
4. Is a two-tier affiliate program a good idea?
Please share what you think of these if you have experience of setting up a successful affiliate program.

1.) % of sale only is best for you e.g. you only pay when they make a sale, % offers more incentive to an affiliate if you have a high end product. Or you could just pay a flat fee say $20 per sale
2.) see above
3.) I prefer one time - but it does depend on your product. IF you can let affiliates know that say you have 90% of the people still signed up after a year then offer a monthly scheme. Or as all of the big poker affiliate schemes do - just offer both!
4.) Two tier is good for your super affiliates
Hope this helps
Dickie Boy